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Records |
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Author |
Marguí, E.; Fontàs, C.; van Meel, K.; Van Grieken, R.; Queralt, I.; Hidalgo, M. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
High-energy polarized-beam energy-dispersive X-ray fluorescence analysis combined with activated thin layers for cadmium determination at trace levels in complex environmental liquid samples |
Type |
A1 Journal article |
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Year |
2008 |
Publication |
Analytical chemistry |
Abbreviated Journal |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
80 |
Issue |
7 |
Pages |
2357-2364 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Corporate Author |
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Thesis |
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Place of Publication |
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Wos |
000254593500015 |
Publication Date |
2008-03-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:68425 |
Serial |
8032 |
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Permanent link to this record |
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Author |
Lindner, H.; Autrique, D.; Garcia, C.C.; Niemax, K.; Bogaerts, A. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Optimized transport setup for high repetition rate pulse-separated analysis in laser ablation-inductively coupled plasma mass spectrometry |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
81 |
Issue |
11 |
Pages |
4241-4248 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
An optimized laser ablation setup, proposed for high repetition rate inductively coupled plasma mass spectrometry (ICPMS) analyses such as 2D imaging or depth profiling, is presented. For such applications, the particle washout time needs to be as short as possible to allow high laser pulse frequencies for reduced analysis time. Therefore, it is desirable to have an ablation setup that operates as a laminar flow reactor (LFR). A top-down strategy was applied that resulted in the present design. In the first step, a previously applied ablation setup was analyzed on the basis of computational fluid dynamics (CFD) results presented by D. Autrique et al. (Spectrochim. Acta, B 2008, 63, 257−270). By means of CFD simulations, the design was modified in such a way that it operated in the LFR regime. Experimental results demonstrate that the current design can indeed be regarded as an LFR. Furthermore, the operation under LFR conditions allowed some insight into the initial radial concentration distribution if the experimental ICPMS signal and analytical expressions are taken into account. Recommendations for a modified setup for more resilient spatial distributions are given. With the present setup, a washout time of 140 ms has been achieved for a 3% signal area criterion. Therefore, 7 Hz repetition rates can be applied with the present setup. Using elementary formulas of the analytical model, an upper bound for the washout times for similar setups can be predicted. The authors believe that the presented setup geometry comes close to the achievable limit for reliable short washout times. |
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Place of Publication |
Washington, D.C. |
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Wos |
000266601800014 |
Publication Date |
2009-04-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700;1520-6882; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
18 |
Open Access |
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Notes |
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Approved |
Most recent IF: 6.32; 2009 IF: 5.214 |
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Call Number |
UA @ lucian @ c:irua:76935 |
Serial |
2492 |
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Permanent link to this record |
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Author |
Martens, T.; Mihailova, D.; van Dijk, J.; Bogaerts, A. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Theoretical characterization of an atmospheric pressure glow discharge used for analytical spectrometry |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
81 |
Issue |
21 |
Pages |
9096-9108 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
We have investigated the plasma processes in an atmospheric pressure glow discharge (APGD) in He used for analytical spectrometry by means of fluid and Monte Carlo (MC) simulations. Typical results include the potential and electric field distributions in the plasma, the density profiles of the various plasma species throughout the discharge, the mean electron energy, as well as the rates of the various collision processes in the plasma, and the relative importance of the different production and loss rates for the various species. The similarities and differences with low-pressure glow discharges are discussed. The main differences are a very small cathode dark space region and a large positive column as well as the dominant role of molecular ions. Some characteristic features of the APGD, such as the occurrence of the different spatial zones in the discharge, are illustrated, with links to experimental observations. |
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Corporate Author |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Wos |
000276191900062 |
Publication Date |
2009-10-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700;1520-6882; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
15 |
Open Access |
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Notes |
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Approved |
Most recent IF: 6.32; 2009 IF: 5.214 |
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Call Number |
UA @ lucian @ c:irua:79554 |
Serial |
3604 |
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Permanent link to this record |
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Author |
van der Snickt, G.; Dik, J.; Cotte, M.; Janssens, K.; Jaroszewicz, J.; de Nolf, W.; Groenewegen, J.; van der Loeff, L. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Characterization of a degraded cadmium yellow (CdS) pigment in an oil painting by means of synchrotron radiation based X-ray techniques |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
81 |
Issue |
7 |
Pages |
2600-2610 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
On several paintings of James Ensor (1860−1949), a gradual fading of originally bright yellow areas, painted with the pigment cadmium yellow (CdS), is observed. Additionally, in some areas exposed to light, the formation of small white-colored globules on top of the original paint surface is observed. In this paper the chemical transformation leading to the color change and to the formation of the globules is elucidated. Microscopic X-ray absorption near-edge spectroscopy (ì-XANES) experiments show that sulfur, originally present in sulfidic form (S2−), is oxidized during the transformation to the sulfate form (S6+). Upon formation (at or immediately below the surface), the highly soluble cadmium sulfate is assumed to be transported to the surface in solution and reprecipitates there, forming the whitish globules. The presence of cadmium sulfate (CdSO4·2H2O) and ammonium cadmium sulfate [(NH4)2Cd(SO4)2] at the surface is confirmed by microscopic X-ray diffraction measurements, where the latter salt is suspected to result from a secondary reaction of cadmium sulfate with ammonia. Measurements performed on cross sections reveal that the oxidation front has penetrated into the yellow paint down to ca. 1−2 ìm. The morphology and elemental distribution of the paint and degradation product were examined by means of scanning electron microscopy equipped with an energy-dispersive spectrometer (SEM-EDS) and synchrotron radiation based micro-X-ray fluorescence spectrometry (SR ì-XRF). In addition, ultraviolet-induced visible fluorescence photography (UIVFP) revealed itself to be a straightforward technique for documenting the occurrence of this specific kind of degradation on a macroscale by painting conservators. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000264759400025 |
Publication Date |
2009-03-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
91 |
Open Access |
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Notes |
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Approved |
Most recent IF: 6.32; 2009 IF: 5.214 |
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Call Number |
UA @ admin @ c:irua:76415 |
Serial |
5501 |
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Permanent link to this record |
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Author |
Marguí, E.; van Meel, K.; Van Grieken, R.; Buendía, A.; Fontás, C.; Hidalgo, M.; Queralt, I. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Method for the determination of Pd-catalyst residues in active pharmaceutical ingredients by means of high-energy polarized-beam energy dispersive X-ray fluorescence |
Type |
A1 Journal article |
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Year |
2009 |
Publication |
Analytical chemistry |
Abbreviated Journal |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
81 |
Issue |
4 |
Pages |
1404-1410 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
In medicinal chemistry, Pd is perhaps the most-widely utilized precious metal, as catalyst in reactions which represent key transformations toward the synthesis of new active pharmaceutical ingredients (APIs). The disadvantage of this metal-catalyzed chemistry is that expensive and toxic metal residues are invariably left bound to the desired product. Thus, stringent regulatory guidelines exist for the amount of residual Pd that a drug candidate is allowed to contain. In this work, a rapid and simple method for the determination of Pd in API samples by high-energy polarized-beam energy dispersive X-ray fluorescence spectrometry has been developed and validated according to the specification limits of current legislation (10 mg kg−1 Pd) and the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH guidelines). Sample and calibration standards preparation includes a first step of homogenization and then, in a second step, the pressing of the powdered material into pellets without any chemical treatment. The use of several synthetic calibration standards made of cellulose to simulate the API matrix appears to be an effective means to obtain reliable calibration curves with a good spread of data points over the working range. With the use of the best measuring conditions, the limit of detection (0.11 mg kg−1 Pd) as well as the limit of quantitation (0.37 mg kg−1 Pd) achieved meet rigorous requirements. The repeatability of the XRF measurement appeared to be less than 2%, while the precision of the whole method was around 7%. Trueness was evaluated by analyzing spiked API samples at the level of the specification limit and calculating the recovery factor, which was better than 95%. To study the applicability of the developed methodology for the intended purpose, three batches of the studied API were analyzed for their Pd content, and the attained results were comparable to those obtained by the daily routine method (acid digestion plus atomic spectroscopy) used in most pharmaceutical laboratories. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Wos |
000263319000015 |
Publication Date |
2009-01-22 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:74340 |
Serial |
8220 |
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Permanent link to this record |
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Author |
Bings, N.H.; Bogaerts, A.; Broekaert, J.A.C. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Atomic spectroscopy: a review |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
82 |
Issue |
12 |
Pages |
4653-4681 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000278616100001 |
Publication Date |
2010-05-13 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700;1520-6882; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
|
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Impact Factor |
6.32 |
Times cited |
65 |
Open Access |
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Notes |
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Approved |
Most recent IF: 6.32; 2010 IF: 5.874 |
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Call Number |
UA @ lucian @ c:irua:82675 |
Serial |
195 |
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Permanent link to this record |
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Author |
Monico, L.; van der Snickt, G.; Janssens, K.; de Nolf, W.; Miliani, C.; Verbeeck, J.; Tian, H.; Tan, H.; Dik, J.; Radepont, M.; Cotte, M. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of synchrotron X-ray spectromicroscopy and related methods : 1 : artificially aged model samples |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
83 |
Issue |
4 |
Pages |
1214-1223 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
On several paintings by artists of the end of the 19th century and the beginning of the 20th Century a darkening of the original yellow areas, painted with the chrome yellow pigment (PbCrO4, PbCrO4·xPbSO4, or PbCrO4·xPbO) is observed. The most famous of these are the various Sunflowers paintings Vincent van Gogh made during his career. In the first part of this work, we attempt to elucidate the degradation process of chrome yellow by studying artificially aged model samples. In view of the very thin (1−3 μm) alteration layers that are formed, high lateral resolution spectroscopic methods such as microscopic X-ray absorption near edge (μ-XANES), X-ray fluorescence spectrometry (μ-XRF), and electron energy loss spectrometry (EELS) were employed. Some of these use synchrotron radiation (SR). Additionally, microscopic SR X-ray diffraction (SR μ-XRD), μ-Raman, and mid-FTIR spectroscopy were employed to completely characterize the samples. The formation of Cr(III) compounds at the surface of the chrome yellow paint layers is particularly observed in one aged model sample taken from a historic paint tube (ca. 1914). About two-thirds of the chromium that is present at the surface has reduced from the hexavalent to the trivalent state. The EELS and μ-XANES spectra are consistent with the presence of Cr2O3·2H2O (viridian). Moreover, as demonstrated by μ-XANES, the presence of another Cr(III) compound, such as either Cr2(SO4)3·H2O or (CH3CO2)7Cr3(OH)2 [chromium(III) acetate hydroxide], is likely. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000287176900011 |
Publication Date |
2011-02-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700;1520-6882; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
113 |
Open Access |
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Notes |
Iuap; Fwo |
Approved |
Most recent IF: 6.32; 2011 IF: 5.856 |
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Call Number |
UA @ lucian @ c:irua:88794UA @ admin @ c:irua:88794 |
Serial |
632 |
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Permanent link to this record |
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Author |
Lindner, H.; Murtazin, A.; Groh, S.; Niemax, K.; Bogaerts, A. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Simulation and experimental studies on plasma temperature, flow velocity, and injector diameter effects for an inductively coupled plasma |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
83 |
Issue |
24 |
Pages |
9260-9266 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
An inductively coupled plasma (ICP) is analyzed by means of experiments and numerical simulation. Important plasma properties are analyzed, namely, the effective temperature inside the central channel and the mean flow velocity inside the plasma. Furthermore, the effect of torches with different injector diameters is studied by the model. The temperature inside the central channel is determined from the end-on collected line-to-background ratio in dependence of the injector gas flow rates. Within the limits of 3% deviation, the results of the simulation and the experiments are in good agreement in the range of flow rates relevant for the analysis of relatively large droplets, i.e., 50 μm. The deviation increases for higher gas flow rates but stays below 6% for all flow rates studied. The velocity of the gas inside the coil region was determined by side-on analyte emission measurements with single monodisperse droplet introduction and by the analysis of the injector gas path lines in the simulation. In the downstream region significantly higher velocities were found than in the upstream region in both the simulation and the experiment. The quantitative values show good agreement in the downstream region. In the upstream region, deviations were found in the absolute values which can be attributed to the flow conditions in that region and because the methods used for velocity determination are not fully consistent. Eddy structures are found in the simulated flow lines. These affect strongly the way taken by the path lines of the injector gas and they can explain the very long analytical signals found in the experiments at low flow rates. Simulations were performed for different injector diameters in order to find conditions where good analyte transport and optimum signals can be expected. The results clearly show the existence of a transition flow rate which marks the lower limit for effective analyte transport conditions through the plasma. A rule-of-thumb equation was extracted from the results from which the transition flow rate can be estimated for different injector diameters and different injector gas compositions. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000297946900013 |
Publication Date |
2011-07-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700;1520-6882; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
34 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 6.32; 2011 IF: 5.856 |
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Call Number |
UA @ lucian @ c:irua:94001 |
Serial |
3009 |
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Permanent link to this record |
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Author |
Monico, L.; van der Snickt, G.; Janssens, K.; de Nolf, W.; Miliani, C.; Dik, J.; Radepont, M.; Hendriks, E.; Geldof, M.; Cotte, M. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of synchrotron X-ray spectromicroscopy and related methods : 2 : original paint layer samples |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
83 |
Issue |
4 |
Pages |
1224-1231 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
The darkening of the original yellow areas painted with the chrome yellow pigment (PbCrO4, PbCrO4·xPbSO4, or PbCrO4·xPbO) is a phenomenon widely observed on several paintings by Vincent van Gogh, such as the famous different versions of Sunflowers. During our previous investigations on artificially aged model samples of lead chromate, we established for the first time that darkening of chrome yellow is caused by reduction of PbCrO4 to Cr2O3·2H2O (viridian green), likely accompanied by the presence of another Cr(III) compound, such as either Cr2(SO4)3·H2O or (CH3CO2)7Cr3(OH)2 [chromium(III) acetate hydroxide]. In the second part of this work, in order to demonstrate that this reduction phenomenon effectively takes place in real paintings, we study original paint samples from two paintings of V. van Gogh. As with the model samples, in view of the thin superficial alteration layers that are present, high lateral resolution spectroscopic methods that make use of synchrotron radiation (SR), such as microscopic X-ray absorption near edge (μ-XANES) and X-ray fluorescence spectrometry (μ-XRF) were employed. Additionally, μ-Raman and mid-FTIR analyses were carried out to completely characterize the samples. On both paint microsamples, the local presence of reduced Cr was demonstrated by means of μ-XANES point measurements. The presence of Cr(III) was revealed in specific areas, in some cases correlated to the presence of Ba(sulfate) and/or to that of aluminum silicate compounds. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000287176900012 |
Publication Date |
2011-02-14 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
84 |
Open Access |
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Notes |
; This research was funded by grants from ESRF (experiment EC-504) and by HASYLAB (experiments 11-20080130 EC and 11-20070157 EC) and was supported by the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16). The text also presents results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) project nos. G.0103.04, G.0689.06, and G.0704.08. The staff of the Van Gogh Museum, Amsterdam, is acknowledged for their agreeable cooperation and for the authorization to publish the images of the paintings in this article. L.M. was financially supported by the Erasmus Placement in the framework of Lifelong Learning Programme (A.Y. 2009-2010). The EU Community's FP7 Research Infrastructures program under the CHARISMA Project (Grant Agreement 228330) is also acknowledged. ; |
Approved |
Most recent IF: 6.32; 2011 IF: 5.856 |
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Call Number |
UA @ admin @ c:irua:88795 |
Serial |
5571 |
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Permanent link to this record |
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Author |
Rouchon, V.; Duranton, M.; Burgaud, C.; Pellizzi, E.; Lavédrine, B.; Janssens, K.; de Nolf, W.; Nuyts, G.; Vanmeert, F.; Hellemans, K. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Room-temperature study of iron gall ink impregnated paper degradation under various oxygen and humidity conditions : time-dependent monitoring by viscosity and X-ray absorption near-edge spectrometry measurements |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
83 |
Issue |
7 |
Pages |
2589-2597 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Many western manuscripts were written using iron gall inks. These inks can damage the paper via two major mechanisms: (a) acid hydrolysis, enhanced by humidity, and (b) oxidative depolymerization provoked by the presence of oxygen and free iron(II) ions. The degradation of unsized Whatman paper impregnated with different combinations of iron sulfate, gallic acid, and gum arabic was studied at room temperature in order to assess the relative importance of each mechanism. The samples were stored in various environments including a dry and/or an oxygen-free atmosphere. The cellulose depolymerization was monitored by viscometry and related to changes in the oxidation state of iron, determined by X-ray absorption near-edge spectrometry. The results indicate that residual amounts of oxygen (less than 0.1%) promote cellulose depolymerization, whereas the level of relative humidity has no impact. The cellulose depolymerization also appears closely correlated to oxidative mechanisms. Regarding the oxidation of iron, it only occurs in the simultaneous presence of oxygen and moisture, suggesting the occurrence of rustlike oxidative mechanisms. Finally, the presence of gallic acid has a strong influence, which is only partially explained by its capacity to reduce iron(III) to iron(II). |
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Corporate Author |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000288887700028 |
Publication Date |
2011-03-04 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
28 |
Open Access |
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Notes |
; This research was supported by the French Ministry of Culture within the National Program of Research (“La conservation des manuscrits: etude du vieillissement naturel de papiers impregnes d'encres ferrogalliques”). It was funded by grants from HASYLAB (experiments I-20090280 EC and II-20060245 EC) and SOLEIL (proposals 20060396 and 20080761) and was supported by the Interuniversity Attraction Poles Programme Belgian Science Policy (1UAP V1/16). The text also presents results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects nos. G.0689.06, G.0704.08 and G017909N. We are thankful to Dr. Dominique Thaudiere, Dr. Solenn Reguer, Dr. Andrea Somogyi, Dr. Karen Appel, Dr. Manuela Borchert, and Dr. Gerald Falkenberg for their assistance and help during the experiments performed at SOLEIL beamline “DIFFABS” and at HASYLAB Beam line “L” respectively. ; |
Approved |
Most recent IF: 6.32; 2011 IF: 5.856 |
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Call Number |
UA @ admin @ c:irua:89593 |
Serial |
5822 |
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Permanent link to this record |
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Author |
Romero-Pastor, J.; Duran, A.; Rodríguez-Navarro, A.B.; Van Grieken, R.; Cardell, C. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Compositional and quantitative microtextural characterization of historic paintings by micro-X-ray diffraction and Raman microscopy |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Analytical chemistry |
Abbreviated Journal |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
83 |
Issue |
22 |
Pages |
8420-8428 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
This work shows the benefits of characterizing historic paintings via compositional and microtextural data from micro-X-ray diffraction (μ-XRD) combined with molecular information acquired with Raman microscopy (RM) along depth profiles in paint stratigraphies. The novel approach was applied to identify inorganic and organic components from paintings placed at the 14th century Islamic UniversityMadrasah Yusufiyyain Granada (Spain), the only Islamic University still standing from the time of Al-Andalus (Islamic Spain). The use of μ-XRD to obtain quantitative microtextural information of crystalline phases provided by two-dimensional diffraction patterns to recognize pigments nature and manufacture, and decay processes in complex paint cross sections, has not been reported yet. A simple Nasrid (14th century) palette made of gypsum, vermilion, and azurite mixed with glue was identified in polychromed stuccos. Here also a Christian intervention was found via the use of smalt, barite, hematite, Brunswick green and gold; oil was the binding media employed. On mural paintings and wood ceilings, more complex palettes dated to the 19th century were found, made of gypsum, anhydrite, barite, dolomite, calcite, lead white, hematite, minium, synthetic ultramarine blue, and black carbon. The identified binders were glue, egg yolk, and oil. |
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Corporate Author |
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Place of Publication |
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Editor |
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Language |
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Wos |
000296830200011 |
Publication Date |
2011-10-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
|
Times cited |
|
Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:92679 |
Serial |
7715 |
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Permanent link to this record |
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Author |
Pilehvar, S.; Mehta, J.; Dardenne, F.; Robbens, J.; Blust, R.; De Wael, K. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Aptasensing of chloramphenicol in the presence of its analogues : reaching the maximum residue limit |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
84 |
Issue |
15 |
Pages |
6753-6758 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
A novel label-free folding induced aptamer-based electrochemical biosensor for the detection of chloramphenicol (CAP) in the presence of its analogues has been developed. CAP is a broad-spectrum antibiotic which has lost its favor due to its serious adverse toxic effects on human health. Aptamers are artificial nucleic acid ligands (ssDNA or RNA) able to specifically recognize a target such as CAP. In this article, the aptamers are fixed onto a gold electrode surface by a self-assembly approach. In the presence of CAP, the unfolded ssDNA on the electrode surface changes to a hairpin structure bringing the target molecules close to the surface and trigger electron transfer. Detection limits were determined to be 1.6×10-9 mol L-1. In addition, thiamphenicol (TAP) and florfenicol (FF), antibiotics with a similar structure to CAP, did not influence the performance of the aptasensor, suggesting a good selectivity of the CAP-aptasensor. Simplicity and lower detection limit (because of the home-selected aptamers) make that the electrochemical aptasensor is suitable for practical use in the detection of CAP in milk samples. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Wos |
000307159200069 |
Publication Date |
2012-06-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
68 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 6.32; 2012 IF: 5.695 |
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Call Number |
UA @ admin @ c:irua:98816 |
Serial |
5477 |
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Permanent link to this record |
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Author |
van der Snickt, G.; Janssens, K.; Dik, J.; de Nolf, W.; Vanmeert, F.; Jaroszewicz, J.; Cotte, M.; Falkenberg, G.; Van der Loeff, L. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Combined use of synchrotron radiation based micro-X-ray fluorescence, micro-X-ray diffraction, micro-X-ray absorption near-edge, and micro-fourier transform infrared spectroscopies for revealing an alternative degradation pathway of the pigment cadmium yellow in a painting by Van Gogh |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
84 |
Issue |
23 |
Pages |
10221-10228 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Over the past years a number of studies have described the instability of the pigment cadmium yellow (CdS). In a previous paper we have shown how cadmium sulfide on paintings by James Ensor oxidizes to CdSO4 center dot H2O. The degradation process gives rise to the fading of the bright yellow color and the formation of disfiguring white crystals that are present on the paint surface in approximately 50 mu m sized globular agglomerations. Here, we study cadmium yellow in the painting “Flowers in a blue vase” by Vincent van Gogh. This painting differs from the Ensor case in the fact that (a) a varnish was superimposed onto the degraded paint surface and (b) the CdS paint area is entirely covered with an opaque crust. The latter obscures the yellow color completely and thus presents a seemingly more advanced state of degradation. Analysis of a cross-sectioned and a crushed sample by combining scanning microscopic X-ray diffraction (mu-XRD), microscopic X-ray absorption near-edge spectroscopy (mu-XANES), microscopic X-ray fluorescence (mu-XRF) based chemical state mapping and scanning microscopic Fourier transform infrared (mu-FT-IR) spectrometry allowed unravelling the complex alteration pathway. Although no crystalline CdSO4 compounds were identified on the Van Gogh paint samples, we conclude that the observed degradation was initially caused by oxidation of the original CdS pigment, similar as for the previous Ensor case. However, due to the presence of an overlying varnish containing lead-based driers and oxalate ions, secondary reactions took place. In particular, it appears that upon the photoinduced oxidation of its sulfidic counterion, the Cd2+ ions reprecipitated at the paint/varnish interface after having formed a complex with oxalate ions that themselves are considered to be degradation products of the resin and/or oil in the varnish. The SO42- anions, for their part, found a suitable reaction partner in Pb2+ ions stemming from a dissolved lead-based siccative that was added to the varnish to promote its drying. The resulting opaque anglesite compound in the varnish, in combination with the underlying CdC2O4 layer at the paint/varnish interface, account for the orange-gray crust that is disfiguring the painting on a macroscopic level. In this way, the results presented in this paper demonstrate how, through a judicious combined use of several microanalytical methods with speciation capabilities, many new insights can be obtained from two minute, but highly complex and heterogeneous paint samples. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000311815300013 |
Publication Date |
2012-08-30 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
59 |
Open Access |
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|
Notes |
; This research was supported by BELSPO via the Interuniversity Attraction Poles Programme (IUAP VI/16) and the S2-ART project (SD/RI/04A) and funded by Grants from the ESRF (EC-442) and PETRA-III (I-20120312 EC). The text also presents results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) project nos. G.0103.04, G.0689.06, and G.0704.08. The staff of the Kroller-Muller Museum and painting conservators Margje Leeuwestein and Esther Van Duijn are acknowledged for this pleasant cooperation and the authorization for the publication of the images in this article. ; |
Approved |
Most recent IF: 6.32; 2012 IF: 5.695 |
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Call Number |
UA @ admin @ c:irua:105971 |
Serial |
5526 |
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Permanent link to this record |
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Author |
De Wael, K.; Daems, D.; Van Camp, G.; Nagels, L.J. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
The use of potentiometric sensors to study (bio)molecular interactions |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
84 |
Issue |
11 |
Pages |
4921-4927 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Potentiometric sensors were used to study molecular interactions in liquid environments, with sensorgram methodology. This is demonstrated with a lipophilic rubber-, and with a collagen based hydrogel sensor coating. The investigated molecules were promazine and tartaric acid respectively. The sensors were placed in a hydrodynamic wall jet system for the recording of sensorgrams. mV sensor responses were first converted to a signal, expressing the concentration of adsorbed organic ions. Using a linearization method, a pseudo first order kinetic model of adsorption was shown to fit the experimental results perfectly. Kass, kon and koff values were calculated.. The technique can be used over 4 decades of concentration, and it is very sensitive to low MW compounds as well as to multiply charged large biomolecules. This study is the first to demonstrate the application of potentiometric sensors as an alternative and complement to SPR methods. |
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Corporate Author |
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Place of Publication |
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Wos |
000304783100041 |
Publication Date |
2012-04-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
10 |
Open Access |
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Notes |
; Financial support for this work was provided by the University of Antwerp by granting D.D. a BOF interdisciplinary research project. We thank J. Everaert for his help in interpreting the results. K.D.W. and D.D. contributed equally to this work. ; |
Approved |
Most recent IF: 6.32; 2012 IF: 5.695 |
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Call Number |
UA @ admin @ c:irua:97520 |
Serial |
5898 |
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Permanent link to this record |
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Author |
Bings, N.H.; Bogaerts, A.; Broekaert, J.A.C. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Atomic spectroscopy |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
85 |
Issue |
2 |
Pages |
670-704 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000313668400013 |
Publication Date |
2012-11-07 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700;1520-6882; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
29 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 6.32; 2013 IF: 5.825 |
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Call Number |
UA @ lucian @ c:irua:104719 |
Serial |
190 |
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Permanent link to this record |
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Author |
Monico, L.; Janssens, K.; Miliani, C.; Brunetti, B.G.; Vagnini, M.; Vanmeert, F.; Falkenberg, G.; Abakumov, A.; Lu, Y.; Tian, H.; Verbeeck, J.; Radepont, M.; Cotte, M.; Hendriks, E.; Geldof, M.; van der Loeff, L.; Salvant, J.; Menu, M.; |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : 3 : synthesis, characterization, and detection of different crystal forms of the chrome yellow pigment |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
85 |
Issue |
2 |
Pages |
860-867 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
The painter, Vincent van Gogh, and some of his contemporaries frequently made use of the pigment chrome yellow that is known to show a tendency toward darkening. This pigment may correspond to various chemical compounds such as PbCrO4 and PbCr1-xSxO4, that may each be present in various crystallographic forms with different tendencies toward degradation. Investigations by X-ray diffraction (XRD), mid-Fourier Transform infrared (FTIR), and Raman instruments (benchtop and portable) and synchrotron radiation-based micro-XRD and X-ray absorption near edge structure spectroscopy performed on oil-paint models, prepared with in-house synthesized PbCrO4 and PbCr1-xSxO4, permitted us to characterize the spectroscopic features of the various forms. On the basis of these results, an extended study has been carried out on historic paint tubes and on embedded paint microsamples taken from yellow-orange/pale yellow areas of 12 Van Gogh paintings, demonstrating that Van Gogh effectively made use of different chrome yellow types. This conclusion was also confirmed by in situ mid-FTIR investigations on Van Goghs Portrait of Gauguin (Van Gogh Museum, Amsterdam). |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000313668400031 |
Publication Date |
2012-10-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700;1520-6882; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
79 |
Open Access |
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Notes |
Goa; Fwo |
Approved |
Most recent IF: 6.32; 2013 IF: 5.825 |
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Call Number |
UA @ lucian @ c:irua:108707UA @ admin @ c:irua:108707 |
Serial |
631 |
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Permanent link to this record |
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Author |
Monico, L.; Janssens, K.; Miliani, C.; van der Snickt, G.; Brunetti, B.G.; Guidi, M.C.; Radepont, M.; Cotte, M. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : 4 : artificial aging of model samples of co-precipitates of lead chromate and lead sulfate |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
85 |
Issue |
2 |
Pages |
860-867 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Previous investigations about the darkening of chrome yellow pigments revealed that this form of alteration is attributable to a reduction of the original Cr(VI) to Cr(III), and that the presence of sulfur-containing compounds, most often sulfates, plays a key role during this process. We recently demonstrated that different crystal forms of chrome yellow pigments (PbCrO4 and PbCr1xSxO4) are present in paintings by Vincent van Gogh. In the present work, we show how both the chemical composition and the crystalline structure of lead chromate-based pigments influence their stability. For this purpose, oil model samples made with in-house synthesized powders of PbCrO4 and PbCr1xSxO4 were artificially aged and characterized. We observed a profound darkening only for those paint models made with PbCr1xSxO4, rich in SO42 (x ≥ 0.4), and orthorhombic phases (>30 wt %). Cr and S K-edge micro X-ray absorption near edge structure investigations revealed in an unequivocal manner the formation of up to about 60% of Cr(III)-species in the outer layer of the most altered samples; conversely, independent of the paint models chemical composition, no change in the S-oxidation state was observed. Analyses employing UVvisible diffuse reflectance and Fourier transform infrared spectroscopy were performed on unaged and aged model samples in order to obtain additional information on the physicochemical changes induced by the aging treatment. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000313668400032 |
Publication Date |
2012-10-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
49 |
Open Access |
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Notes |
; This research was supported by grants from ESRF (experiment EC-799), the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16), and the BELSPO-SDD S2-ART (SD/RI/04) project. The text also presents results from GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and FWO (Brussels, Belgium) projects G.0704.08 and G.01769.09. The EU FP7 programme CHARISMA (Grant Agreement 228330) and MIUR (PRIN08, Materiali e sistemi innovativi per la conservazione dell'arte contemporanea 2008 FFXXN9) are also acknowledged. ; |
Approved |
Most recent IF: 6.32; 2013 IF: 5.825 |
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Call Number |
UA @ admin @ c:irua:110471 |
Serial |
5569 |
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Permanent link to this record |
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Author |
Hamidi-Asl, E.; Daems, D.; De Wael, K.; Van Camp, G.; Nagels, L.J. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Concentration related response potentiometric titrations to study the interaction of small molecules with large biomolecules |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
86 |
Issue |
24 |
Pages |
12243-12249 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
In the present article, the utility of a special potentiometric titration approach for recognition and calculation of biomolecule/small molecule interactions is reported. This approach is fast, sensitive, reproducible and inexpensive in comparison to the other methods for the determination of the association constant values (Ka) and the interaction energies (ΔG). The potentiometric titration measurement is based on the use of a classical polymeric membrane indicator electrode in a solution of the small molecule ligand. The biomolecule is used as a titrant. The potential is measured versus a reference electrode and transformed to a concentration related signal over the entire concentration interval, also at low concentrations, where the mV (y-axis) versus logcanalyte (x-axis) potentiometric calibration curve is not linear. In the procedure, the Ka is calculated for the interaction of cocaine with a cocaine binding aptamer and with an anti-cocaine antibody. To study the selectivity and cross-reactivity, other oligonucleotides and aptamers are tested, as well as other small ligand molecules such as tetrakis (4-chlorophenyl)borate, metergoline, lidocaine, and bromhexine. The calculated Ka compared favorably to the value reported in the literature using SPR. The potentiometric titration approach called Concentration related Response Potentiometry, is used to study molecular interaction for 7 macromolecular target molecules and 4 small molecule ligands. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Wos |
000346683900048 |
Publication Date |
2014-11-13 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
10 |
Open Access |
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Notes |
; Financial support for this work was provided by the University of Antwerp by granting L.J.N., K.D.W, G.V.C., and Ronny Blust a POC interdisciplinary research project. ; |
Approved |
Most recent IF: 6.32; 2014 IF: 5.636 |
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Call Number |
UA @ admin @ c:irua:120164 |
Serial |
5548 |
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Permanent link to this record |
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Author |
Monico, L.; Janssens, K.; Vanmeert, F.; Cotte, M.; Brunetti, B.G.; van der Snickt, G.; Leeuwestein, M.; Plisson, J.S.; Menu, M.; Miliani, C. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : part 5 : effects of nonoriginal surface coatings into the nature and distribution of chromium and sulfur species in chrome yellow paints |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
86 |
Issue |
21 |
Pages |
10804-10811 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
The darkening of lead chromate yellow pigments, caused by a reduction of the chromate ions to Cr(III) compounds, is known to affect the appearance of several paintings by Vincent van Gogh. In previous papers of this series, we demonstrated that the darkening is activated by light and depends on the chemical composition and crystalline structure of the pigments. In this work, the results of Part 2 are extended and complemented with a new study aimed at deepening the knowledge of the nature and distribution of Cr and S species at the interface between the chrome yellow paint and the nonoriginal coating layer. For this purpose, three microsamples from two varnished paintings by Van Gogh and a waxed low relief by Gauguin (all originally uncoated) have been examined. Because nonoriginal coatings are often present in artwork by Van Gogh and contemporaries, the understanding of whether or not their application has influenced the morphological and/or physicochemical properties of the chrome yellow paint underneath is relevant in view of the conservation of these masterpieces. In all the samples studied, microscopic X-ray fluorescence (mu-XRF) and X-ray absorption near edge structure (mu-XANES) investigations showed that Cr(III)-based alteration products are present in the form of grains inside the coating (generally enriched of S species) and also homogeneously widespread at the paint surface. The distribution of Cr(III) species may be explained by the mechanical friction caused by the coating application by brush that picked up and redistributed the superficial Cr compounds, likely already present in the reduced state as result of the photodegradation process. The analysis of the XANES profiles allowed us to obtain new insights into the nature of the Cr(III) alteration products, that were identified as sulfate-, oxide-, organo-metal-, and chloride-based compounds. Building upon the knowledge acquired through the examination of original paint samples and from the investigation of aged model paints in the last Part 4 paper, in this study we aim to characterize a possible relation between the chemical composition of the coating and the chrome yellow degradation pathways by studying photochemically aged model samples covered with a dammar varnish contaminated with sulfide and sulfate salts. Cr speciation results did not show any evidence of the active role of the varnish and added S species on the reduction process of chrome yellows. |
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Wos |
000344510200043 |
Publication Date |
2014-10-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
25 |
Open Access |
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Notes |
; This research was supported by the Italian projects PRIN (SICH) and PON (ITACHA). The text also presents results from Interuniversity Attraction Poles Programme Belgian Science Policy (S2-ART project S4DA), GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. ESRF is acknowledged for the grants received (experiments EC-799 and EC-1051). L.M. acknowledges the CNR for the financial support received in the framework of the Short Term Mobility Programme 2013. Thanks are expressed to Ella Hendriks (Van Gogh Museum, Amsterdam) and Muriel Geldof (Cultural Heritage Agency of The Netherlands) for selecting and sharing the information on the cross-section taken from Bank of the Seine. All the staff of the Van Gogh Museum, the Kroller-Muller Museum, and the Musee d'Orsay are acknowledged for the agreeable cooperation. ; |
Approved |
Most recent IF: 6.32; 2014 IF: 5.636 |
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Call Number |
UA @ admin @ c:irua:122100 |
Serial |
5570 |
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Permanent link to this record |
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Author |
Anaf, W.; Trashin, S.; Schalm, O.; van Dorp, D.; Janssens, K.; De Wael, K. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Electrochemical photodegradation study of semiconductor pigments : influence of environmental parameters |
Type |
A1 Journal article |
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Year |
2014 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
86 |
Issue |
19 |
Pages |
9742-9748 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES) |
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Abstract |
Chemical transformations in paintings often induce discolorations, disturbing the appearance of the image. For an appropriate conservation of such valuable and irreplaceable heritage objects, it is important to have a good know-how on the degradation processes of the (historical) materials: which pigments have been discolored, what are the responsible processes, and which (environmental) conditions have the highest impact on the pigment degradation and should be mitigated. Pigment degradation is already widely studied, either by analyzing historical samples or by accelerated weathering experiments on dummies. However, in historic samples several processes may have taken place, increasing the complexity of the current state, while aging experiments are time-consuming due to the often extended aging period. An alternative method is proposed for a fast monitoring of degradation processes of semiconductor pigments, using an electrochemical setup mimicking the real environment and allowing the identification of harmful environmental parameters for each pigment. Examples are given for the pigments cadmium yellow (CdS) and vermilion (α-HgS). |
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Place of Publication |
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Language |
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Wos |
000343017100058 |
Publication Date |
2014-08-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
18 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 6.32; 2014 IF: 5.636 |
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Call Number |
UA @ admin @ c:irua:118834 |
Serial |
5593 |
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Permanent link to this record |
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Author |
Ranjbari, E.; Hadjmohammadi, M.R.; Kiekens, F.; De Wael, K. |
![goto web page url](http://nano.uantwerpen.be/nanorefs/img/www.gif)
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Mixed hemi/ad-micelle sodium dodecyl sulfate-coated magnetic iron oxide nanoparticles for the efficient removal and trace determination of rhodamine-B and rhodamine-6G |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
87 |
Issue |
15 |
Pages |
7894-7901 |
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Keywords |
A1 Journal article; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Mixed hemi/ad-micelle sodium dodecyl sulfate (SDS)-coated magnetic iron oxide nanoparticles (MHAMS-MIONPs) were used as an efficient adsorbent for both removal and preconcentration of two important carcinogenic xanthine dyes named rhodamine-B (RB) and rhodamine-6G (RG). To gain insight in the configuration of SDS molecules on the surface of MIONPs, zeta potential measurements were performed in different [SDS]/[MIONP] ratios. Zeta potential data indicated that mixed hemi/ad-micelle MHAM was formed in [SDS]/[MIONP] ratios over the range of 1.1 to 7.3. Parameters affecting the adsorption of dyes were optimized as removal efficiency by one variable at-a-time and response surface methodology; the obtained removal efficiencies were ∼100%. Adsorption kinetic and equilibrium studies, under the optimum condition (pH = 2; amount of MIONPs = 87.15 mg; [SDS]/[MIONP] ratio = 2.9), showed that adsorption of both dyes are based on the pseudo-second-order and the Langmuir isotherm models, respectively. The maximum adsorption capacities for RB and RG were 385 and 323 mg g1, respectively. MHAMS-MIONPs were also applied for extraction of RB and RG. Under optimum conditions (pH = 2; amount of damped MHAMS-MIONPs = 90 mg; eluent solvent volume = 2.6 mL of 3% acetic acid in acetonitrile), extraction recoveries for 0.5 mg L1 of RB and RG were 98% and 99%, with preconcentration factors of 327 and 330, respectively. Limit of detection obtained for rhodamine dyes were <0.7 ng mL1. Finally, MHAMS-MIONPs were successfully applied for both removal and trace determination of RB and RG in environmental and wastewater samples. |
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Place of Publication |
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Wos |
000359277900056 |
Publication Date |
2015-07-08 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
36 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 6.32; 2015 IF: 5.636 |
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Call Number |
UA @ admin @ c:irua:126583 |
Serial |
5730 |
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Permanent link to this record |
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Author |
Aghaei, M.; Lindner, H.; Bogaerts, A. |
![goto web page url](http://nano.uantwerpen.be/nanorefs/img/www.gif)
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Ion Clouds in the Inductively Coupled Plasma Torch: A Closer Look through Computations |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
88 |
Issue |
88 |
Pages |
8005-8018 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
We have computationally investigated the introduction of copper elemental particles in an inductively coupled plasma torch connected to a sampling cone, including for the first time the ionization of the sample. The sample is inserted as liquid particles, which are followed inside the entire torch, i.e., from the injector inlet up to the ionization and reaching the sampler. The spatial position of the ion clouds inside the torch as well as detailed information on the copper species fluxes at the position of the sampler orifice and the exhausts of the torch are provided. The effect of on- and off-axis injection is studied. We clearly show that the ion clouds of on-axis injected material are located closer to the sampler with less radial diffusion. This guarantees a higher transport efficiency through the sampler cone. Moreover, our model reveals the optimum ranges of applied power and flow rates, which ensure the proper position of ion clouds inside the torch, i.e., close enough to the sampler to increase the fraction that can enter the mass spectrometer and with minimum loss of material toward the exhausts as well as a sufficiently high plasma temperature for efficient ionization. |
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Research Group PLASMANT, Chemistry Department, University of Antwerp , Universiteitsplein 1, 2610 Antwerp, Belgium |
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Language |
English |
Wos |
000381654800020 |
Publication Date |
2016-07-26 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
9 |
Open Access |
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Notes |
The authors gratefully acknowledge financial support from the Fonds voor Wetenschappelijk Onderzoek (FWO), Grant Number 6713. The computational work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the UA. |
Approved |
Most recent IF: 6.32 |
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Call Number |
PLASMANT @ plasmant @ c:irua:135644 |
Serial |
4293 |
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Permanent link to this record |
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Author |
Ayalew, E.; Janssens, K.; De Wael, K. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Unraveling the reactivity of minium towards bicarbonate and the role of lead oxides therein |
Type |
A1 Journal article |
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Year |
2016 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
88 |
Issue |
3 |
Pages |
1564-1569 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Understanding the reactivity of (semiconductor) pigments provides vital information on how to improve conservation strategies for works of art in order to avoid rapid degradation of the pigments. This study focuses on the photoactivity of minium (Pb3O4), a semiconductor pigment, that gives rise to strong discoloration phenomena upon exposure to various environmental conditions. To demonstrate its photoactivity, an electrochemical setup with minium-modified graphite electrode (C|Pb3O4) was used. It is confirmed that minium is a p-type semiconductor which is photoactive during illumination and becomes inactive in the dark. Raman measurements confirm the formation of the degradation products. The photoactivity of a semiconductor pigment is partly defined by the presence of lead oxide (PbO) impurities; these introduce new states in the original band gap. It will be experi-mentally evidenced that the presence of PbO particles in minium leads to an upward shift of the valence band that reduces the band gap. Thus, upon photoexcitation, the electron/hole separation is more easily initialized. The PbO/Pb3O4 composite electrodes demonstrate a higher reductive photocurrent compared to the photocurrent registered at pure PbO or Pb3O4 modified electrodes. Upon exposure to light with energy close to and above the band gap, electrons are excited from the valence band to the conduction band to initialize the reduction of Pb(IV) to Pb(II), resulting in the initial formation of PbO. However in the presence of bicarbonate ions, a significantly higher photoreduction current is recorded since the PbO reacts further to form hydrocerussite. Therefore the presence of bicarbonates in the environment stimulates the photodecomposition process of minium and plays an important role in the degradation process. |
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Wos |
000369471100014 |
Publication Date |
2015-12-31 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
9 |
Open Access |
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Notes |
; The authors acknowledge Sanne Aerts from the Laboratory of Adsorption and Catalysis (LADCA) of the University of Antwerp for her help with the UV-vis-DR. Financial support from the SOLARPAINT BOF-GOA project (University of Antwerp Research Council) is acknowledged. The authors are also indebted to F. Vanmeert for performing the XRD measurements. ; |
Approved |
Most recent IF: 6.32 |
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Call Number |
UA @ admin @ c:irua:129963 |
Serial |
5888 |
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Permanent link to this record |
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Author |
Cagno, S.; Brede, D.A.; Nuyts, G.; Vanmeert, F.; Pacureanu, A.; Tucoulou, R.; Cloetens, P.; Falkenberg, G.; Janssens, K.; Salbu, B.; Lind, O.C. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Combined computed nanotomography and nanoscopic x-ray fluorescence imaging of cobalt nanoparticles in caenorhabditis elegans |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
89 |
Issue |
21 |
Pages |
11435-11442 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Synchrotron radiation phase-contrast computed nanotomography (nano-CT) and two-and three-dimensional (2D and 3D) nanoscopic X-ray fluorescence (nano-XRF) were used to investigate the internal distribution of engineered-cobalt nanoparticles (Co NPs) in exposed individuals of the nematode Caenorhabditis elegans. Whole-nematodes and selected tissues and organs were 3D-rendered: anatomical 3D renderings with 50 nm voxel size enabled the visualization of spherical nanoparticle aggregates. with size tip to 200 nm within intact C. elegans. A 20 X 37 nm(2) high-brilliance beam was employed to obtain XRF elemental distribution maps of entire nematodes or anatomical details such as embryos, which could be compared with the CT data, These maps showed Co NPs to be predominantly present within the intestine and the epithelium, and they were not colocalized with Zn granules found in the lysosonie-containing vesicles or Fe agglomerates in the intestine. Iterated XRF scanning of a specimen at 0 degrees and 90 degrees angles suggested that NP aggregates were translocated into tissues outside of the intestinal lumen. Virtual-slicing by means of 2D XRF tomography, combined with holotomography, indicated presumable presence of individual NP aggregates inside the uterus and within embryos. |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000414887000041 |
Publication Date |
2017-10-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
13 |
Open Access |
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Notes |
; This study has been funded by the Norwegian Research Council through its Centre of Excellence (CoE) funding scheme (Project 223268/F50). We gratefully acknowledge ESRF and DESY for granting beamtime and Karl Andreas Jensen for performing ICPMS analysis. We thank Erica Maremonti for supplying the phase-contrast image used in Figure ^1A. ; |
Approved |
Most recent IF: 6.32 |
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Call Number |
UA @ admin @ c:irua:147383 |
Serial |
5520 |
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Permanent link to this record |
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Author |
Fuchs, J.; Aghaei, M.; Schachel, T.D.; Sperling, M.; Bogaerts, A.; Karst, U. |
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Title |
Impact of the Particle Diameter on Ion Cloud Formation from Gold Nanoparticles in ICPMS |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
90 |
Issue |
17 |
Pages |
10271-10278 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The unique capabilities of microsecond dwell time (DT) single-particle inductively coupled plasma mass spectrometry (spICPMS) were utilized to characterize the cloud of ions generated from the introduction of suspensions of gold nanoparticles (AuNPs) into the plasma. A set of narrowly distributed particles with diameters ranging from 15.4 to 100.1 nm was synthesized and characterized according to established protocols. Statistically significant numbers of the short transient spICPMS events were evaluated by using 50 μs DT for their summed intensity, maximum intensity, and duration, of which all three were found to depend on the particle diameter. The summed intensity increases from 10 to 1661 counts and the maximum intensity from 6 to 309 counts for AuNPs with diameters from 15.4 to 83.2 nm. The event duration rises from 322 to 1007 μs upon increasing AuNP diameter. These numbers represent a comprehensive set of key data points of the ion clouds generated in ICPMS from AuNPs. The extension of event duration is of high interest to appoint the maximum possible particle number concentration at which separation of consecutive events in spICPMS can still be achieved. Moreover, the combined evaluation of all above-mentioned ion cloud characteristics can explain the regularly observed prolonged single-particle events. The transport and ionization behavior of AuNPs in the ICP was also computationally modeled to gain insight into the size-dependent signal generation. The simulated data reveals that the plasma temperature, and therefore the point of ionization of the particles, is the same for all diameters. However, the maximum number density of Au+, as well as the extent of the ion cloud, depends on the particle diameter, in agreement with the experimental data, and it provides an adequate explanation for the observed ion cloud characteristics. |
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Place of Publication |
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Language |
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Wos |
000444060600028 |
Publication Date |
2018-09-04 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-2700 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
5 |
Open Access |
OpenAccess |
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Notes |
We thank Dr. Harald Rösner from the Institute of Materials Physics of the University of Münster for the TEM imaging. |
Approved |
Most recent IF: 6.32 |
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Call Number |
PLASMANT @ plasmant @c:irua:153651 |
Serial |
5057 |
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Permanent link to this record |
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Author |
Gorbanev, Y.; Privat-Maldonado, A.; Bogaerts, A. |
![goto web page url](http://nano.uantwerpen.be/nanorefs/img/www.gif)
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Title |
Analysis of Short-Lived Reactive Species in Plasma–Air–Water Systems: The Dos and the Do Nots |
Type |
A1 Journal Article |
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Year |
2018 |
Publication |
Analytical Chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
90 |
Issue |
22 |
Pages |
13151-13158 |
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Keywords |
A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ; |
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Abstract |
This Feature addresses the analysis of the reactive species generated by nonthermal atmospheric
pressure plasmas, which are widely employed in industrial and biomedical research, as well as first
clinical applications. We summarize the progress in detection of plasma-generated short-lived
reactive oxygen and nitrogen species in aqueous solutions, discuss the potential and limitations of
various analytical methods in plasma−liquid systems, and provide an outlook on the possible future
research goals in development of short-lived reactive species analysis methods for a general
nonspecialist audience. |
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000451246100002 |
Publication Date |
2018-11-20 |
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ISSN |
0003-2700 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
17 |
Open Access |
Not_Open_Access |
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Notes |
European Commission, 743151 ; This work was supported by the European Marie Sklodowska- Curie Individual Fellowship within Horizon2020 (“LTPAM”, Grant No. 743151). |
Approved |
Most recent IF: 6.32 |
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Call Number |
PLASMANT @ plasmant @c:irua:156301 |
Serial |
5152 |
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Author |
De Jong, M.; Florea, A.; de Vries, A.-M.; van Nuijs, A.L.N.; Covaci, A.; Van Durme, F.; Martins, J.C.; Samyn, N.; De Wael, K. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Levamisole : a common adulterant in cocaine street samples hindering electrochemical detection of cocaine |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
90 |
Issue |
8 |
Pages |
5290-5297 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre |
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Abstract |
The present work investigates the electrochemical determination of cocaine in the presence of levamisole, one of the most common adulterants found in cocaine street samples. Levamisole misleads cocaine color tests, giving a blue color (positive test) even in the absence of cocaine. Moreover, the electrochemical detection of cocaine is also affected by the presence of levamisole, with a suppression of the oxidation signal of cocaine. When levamisole is present in the sample in ratios higher than 1:1, the cocaine signal is no longer detected, thus leading to false negative results. Mass spectrometry and nuclear magnetic resonance were used to investigate if the signal suppression is due to the formation of a complex between cocaine and levamisole in bulk solution. Strategies to eliminate this suppressing effect are further suggested in this manuscript. In a first approach, the increase of the pH of the sample solution from pH 7 to pH 12 allowed the voltammetric determination of cocaine in the presence of levamisole in a concentration range from 10 to 5000 μM at nonmodified graphite disposable electrodes with a detection limit of 5 μM. In a second approach, the graphite electrode was cathodically pretreated, resulting in the presence of oxidation peaks of both cocaine and levamisole, with a detection limit for cocaine of 3 μM over the linear range of concentrations from 10 to 2500 μM. Both these strategies have been successfully applied for the simultaneous detection of cocaine and levamisole in three street samples on unmodified graphite disposable electrodes. |
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000430512200049 |
Publication Date |
2018-02-23 |
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ISSN |
0003-2700; 5206-882x |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
8 |
Open Access |
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Notes |
; This project has received funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement No. 753223 Narcoreader. This work was also supported by BR/314/PI/ APTADRU Project and IOF-SBO (UAntwerp). Alexander van Nuijs acknowledges the Research Foundation-Flanders (FWO) for his postdoctoral fellowship. ; |
Approved |
Most recent IF: 6.32 |
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Call Number |
UA @ admin @ c:irua:149528 |
Serial |
5693 |
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Author |
Vanmeert, F.; de Nolf, W.; De Meyer, S.; Dik, J.; Janssens, K. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Macroscopic X-ray powder diffraction scanning, a new method for highly selective chemical imaging of works of art : instrument optimization |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
90 |
Issue |
11 |
Pages |
6436-6444 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
In the past decade macroscopic X-ray fluorescence imaging (MA-XRF) has become established as a method for the noninvasive investigation of flat painted surfaces, yielding large scale elemental maps. MA-XRF is limited by a lack of specificity, only allowing for indirect pigment identification based on the simultaneous presence of chemical elements. The high specificity of X-ray powder diffraction (XRPD) mapping is already being exploited at synchrotron facilities for investigations at the (sub)microscopic scale, but the technique has not yet been employed using lab sources. In this paper we present the development of a novel MA-XRPD/XRF instrument based on a laboratory X-ray source. Several combinations of X-ray sources and area detectors are evaluated in terms of their spatial and angular resolution and their sensitivity. The highly specific imaging capability of the combined MA-XRPD/XRF instrument is demonstrated on a 15th/16th century illuminated manuscript directly revealing the distribution of a large number of inorganic pigments, including the uncommon yellow pigment massicot (o-PbO). The case study illustrates the wealth of new mapping information that can be obtained in a noninvasive manner using the laboratory MA-XRPD/XRF instrument. |
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000434893200019 |
Publication Date |
2018-04-06 |
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ISSN |
0003-2700; 5206-882x |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
11 |
Open Access |
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Notes |
; The authors thank the persons involved at Incoatec GmbH, imXPAD SAS and Dectris Ltd. for loaning us some of their products over the past years. We acknowledge financial support from BELSPO (Brussels) S2-ART, the NWO (The Hague) Science4Arts “ReVisRembrandt” Project and GOA Project Solarpaint (University of Antwerp Research Council). Photo Copyright Geert Van der Snickt, 2008 for the photograph of the illuminated manuscript in the TOC graphic. ; |
Approved |
Most recent IF: 6.32 |
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Call Number |
UA @ admin @ c:irua:151993 |
Serial |
5701 |
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Author |
Vanmeert, F.; de Nolf, W.; Dik, J.; Janssens, K. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Macroscopic X-ray powder diffraction scanning : possibilities for quantitative and depth-selective parchment analysis |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
90 |
Issue |
11 |
Pages |
6445-6452 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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At or below the surface of painted works of art, valuable information is present that provides insights into an objects past, such as the artists technique and the creative process that was followed or its conservation history but also on its current state of preservation. Various noninvasive techniques have been developed over the past 2 decades that can probe this information either locally (via point analysis) or on a macroscopic scale (e.g., full-field imaging and raster scanning). Recently macroscopic X-ray powder diffraction (MA-XRPD) mapping using laboratory X-ray sources was developed. This method can visualize highly specific chemical distributions at the macroscale (dm(2)). In this work we demonstrate the synergy between the quantitative aspects of powder diffraction and the noninvasive scanning capability of MA-XRPD highlighting the potential of the method to reveal new types of information. Quantitative data derived from a 15th/16th century illuminated sheet of parchment revealed three lead white pigments with different hydrocerussite-cerussite compositions in specific pictorial elements, while quantification analysis of impurities in the blue azurite pigment revealed two distinct azurite types: one rich in barite and one in quartz. Furthermore, on the same artifact, the depth-selective possibilities of the method that stem from an exploitation of the shift of the measured diffraction peaks with respect to reference data are highlighted. The influence of different experimental parameters on the depth-selective analysis results is briefly discussed. Promising stratigraphic information could be obtained, even though the analysis is hampered by not completely understood variations in the unit cell dimensions of the crystalline pigment phases. |
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000434893200020 |
Publication Date |
2018-04-06 |
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ISSN |
0003-2700; 5206-882x |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
6 |
Open Access |
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Notes |
; The authors thank Incoatec GmbH for giving us the opportunity to test the I mu S Cu X-ray source. We acknowledge financial support from BELSPO (Brussels) S2-ART, the NWO (The Hague) Science4Arts “ReVisRembrandt” project, and GOA Project Solarpaint (University of Antwerp Research Council). Photo Copyright Geert Van der Snickt, 2008 for the photograph of the illuminated manuscript in the TOC graphic. ; |
Approved |
Most recent IF: 6.32 |
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Call Number |
UA @ admin @ c:irua:151994 |
Serial |
5702 |
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Permanent link to this record |
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Author |
De Jong, M.; Florea, A.; Eliaerts, J.; Van Durme, F.; Samyn, N.; De Wael, K. |
![goto web page (via DOI) doi](http://nano.uantwerpen.be/nanorefs/img/doi.gif)
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Title |
Tackling poor specificity of cocaine color tests by electrochemical strategies |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
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Volume ![sorted by Volume (numeric) field, ascending order (up)](img/sort_asc.gif) |
90 |
Issue |
11 |
Pages |
6811-6819 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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This paper presents electrochemical strategies for the fast screening of cocaine and most common cutting agents found in seized drug samples. First, a study on the performance of Scott color tests on cocaine and a wide range of cutting agents is described. The cutting agents causing false positive or false negative results when in mixture with cocaine are identified. To overcome the lack of specificity of color tests, we further propose a fast screening strategy by means of square wave voltammetry on disposable graphite screen printed electrodes, which reveals the unique fingerprint of cocaine and cutting agents. By employing a forward and backward scan and by a dual pH strategy, we enrich the electrochemical fingerprint and enable the simultaneous detection of cocaine and cutting agents. The effectiveness of the developed strategies was tested for the detection of cocaine in seized cocaine samples and compared with the color tests. Moreover, we prove the usefulness of square wave voltammetry for predicting possible interfering agents in color tests, based on the reduction peak of cobalt thiocyanate. The developed electrochemical strategies allow for a quick screening of seized cocaine samples resulting in a selective identification of drugs and cutting agents. |
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Wos |
000434893200066 |
Publication Date |
2018-05-09 |
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ISSN |
0003-2700; 5206-882x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.32 |
Times cited |
7 |
Open Access |
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Notes |
; This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No. 753223 Narcoreader. This work was also supported by Grants BR/314 /PI/APTADRU and IOF-SBO. ; |
Approved |
Most recent IF: 6.32 |
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Call Number |
UA @ admin @ c:irua:151316 |
Serial |
5867 |
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Permanent link to this record |