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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.
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
Year 2013 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 85 Issue 2 Pages 860-867
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000313668400032 Publication Date 2012-10-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 49 Open Access
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 (down) Most recent IF: 6.32; 2013 IF: 5.825
Call Number UA @ admin @ c:irua:110471 Serial 5569
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Author Pilehvar, S.; Mehta, J.; Dardenne, F.; Robbens, J.; Blust, R.; De Wael, K.
Title Aptasensing of chloramphenicol in the presence of its analogues : reaching the maximum residue limit Type A1 Journal article
Year 2012 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 84 Issue 15 Pages 6753-6758
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000307159200069 Publication Date 2012-06-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 68 Open Access
Notes ; ; Approved (down) Most recent IF: 6.32; 2012 IF: 5.695
Call Number UA @ admin @ c:irua:98816 Serial 5477
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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.
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
Year 2012 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 84 Issue 23 Pages 10221-10228
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000311815300013 Publication Date 2012-08-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 59 Open Access
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 (down) Most recent IF: 6.32; 2012 IF: 5.695
Call Number UA @ admin @ c:irua:105971 Serial 5526
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Author De Wael, K.; Daems, D.; Van Camp, G.; Nagels, L.J.
Title The use of potentiometric sensors to study (bio)molecular interactions Type A1 Journal article
Year 2012 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 84 Issue 11 Pages 4921-4927
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000304783100041 Publication Date 2012-04-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 10 Open Access
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 (down) Most recent IF: 6.32; 2012 IF: 5.695
Call Number UA @ admin @ c:irua:97520 Serial 5898
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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.
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
Year 2011 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 83 Issue 4 Pages 1214-1223
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000287176900011 Publication Date 2011-02-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 113 Open Access
Notes Iuap; Fwo Approved (down) Most recent IF: 6.32; 2011 IF: 5.856
Call Number UA @ lucian @ c:irua:88794UA @ admin @ c:irua:88794 Serial 632
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Author Lindner, H.; Murtazin, A.; Groh, S.; Niemax, K.; Bogaerts, A.
Title Simulation and experimental studies on plasma temperature, flow velocity, and injector diameter effects for an inductively coupled plasma Type A1 Journal article
Year 2011 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 83 Issue 24 Pages 9260-9266
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000297946900013 Publication Date 2011-07-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 34 Open Access
Notes Approved (down) Most recent IF: 6.32; 2011 IF: 5.856
Call Number UA @ lucian @ c:irua:94001 Serial 3009
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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.
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
Year 2011 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 83 Issue 4 Pages 1224-1231
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000287176900012 Publication Date 2011-02-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 84 Open Access
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 (down) Most recent IF: 6.32; 2011 IF: 5.856
Call Number UA @ admin @ c:irua:88795 Serial 5571
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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.
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
Year 2011 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 83 Issue 7 Pages 2589-2597
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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).
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000288887700028 Publication Date 2011-03-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 28 Open Access
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 (down) Most recent IF: 6.32; 2011 IF: 5.856
Call Number UA @ admin @ c:irua:89593 Serial 5822
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Author Bings, N.H.; Bogaerts, A.; Broekaert, J.A.C.
Title Atomic spectroscopy: a review Type A1 Journal article
Year 2010 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 82 Issue 12 Pages 4653-4681
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000278616100001 Publication Date 2010-05-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 65 Open Access
Notes Approved (down) Most recent IF: 6.32; 2010 IF: 5.874
Call Number UA @ lucian @ c:irua:82675 Serial 195
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Author Lindner, H.; Autrique, D.; Garcia, C.C.; Niemax, K.; Bogaerts, A.
Title Optimized transport setup for high repetition rate pulse-separated analysis in laser ablation-inductively coupled plasma mass spectrometry Type A1 Journal article
Year 2009 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 81 Issue 11 Pages 4241-4248
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000266601800014 Publication Date 2009-04-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 18 Open Access
Notes Approved (down) Most recent IF: 6.32; 2009 IF: 5.214
Call Number UA @ lucian @ c:irua:76935 Serial 2492
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Author Martens, T.; Mihailova, D.; van Dijk, J.; Bogaerts, A.
Title Theoretical characterization of an atmospheric pressure glow discharge used for analytical spectrometry Type A1 Journal article
Year 2009 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 81 Issue 21 Pages 9096-9108
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000276191900062 Publication Date 2009-10-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 15 Open Access
Notes Approved (down) Most recent IF: 6.32; 2009 IF: 5.214
Call Number UA @ lucian @ c:irua:79554 Serial 3604
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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.
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
Year 2009 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 81 Issue 7 Pages 2600-2610
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000264759400025 Publication Date 2009-03-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 91 Open Access
Notes Approved (down) Most recent IF: 6.32; 2009 IF: 5.214
Call Number UA @ admin @ c:irua:76415 Serial 5501
Permanent link to this record
 
 
Author Bings, N.H.; Bogaerts, A.; Broekaert, J.A.C.
Title Atomic spectroscopy Type A1 Journal article
Year 2008 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 80 Issue 12 Pages 4317-4347
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000256763400006 Publication Date 2008-05-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 53 Open Access
Notes Approved (down) Most recent IF: 6.32; 2008 IF: 5.712
Call Number UA @ lucian @ c:irua:69437 Serial 191
Permanent link to this record
 
 
Author Dik, J.; Janssens, K.; van der Snickt, G.; van der Loeff, L.; Rickers, K.; Cotte, M.
Title Visualization of a lost painting by Vincent van Gogh using synchrotron radiation based X-ray fluorescence elemental mapping Type A1 Journal article
Year 2008 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 80 Issue 16 Pages 6436-6442
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Vincent van Gogh (1853−1890), one of the founding fathers of modern painting, is best known for his vivid colors, his vibrant painting style, and his short but highly productive career. His productivity is even higher than generally realized, as many of his known paintings cover a previous composition. This is thought to be the case in one-third of his early period paintings. Van Gogh would often reuse the canvas of an abandoned painting and paint a new or modified composition on top. These hidden paintings offer a unique and intimate insight into the genesis of his works. Yet, current museum-based imaging tools are unable to properly visualize many of these hidden images. We present the first-time use of synchrotron radiation based X-ray fluorescence mapping, applied to visualize a womans head hidden under the work Patch of Grass by Van Gogh. We recorded decimeter-scale, X-ray fluorescence intensity maps, reflecting the distribution of specific elements in the paint layers. In doing so we succeeded in visualizing the hidden face with unprecedented detail. In particular, the distribution of Hg and Sb in the red and light tones, respectively, enabled an approximate color reconstruction of the flesh tones. This reconstruction proved to be the missing link for the comparison of the hidden face with Van Goghs known paintings. Our approach literally opens up new vistas in the nondestructive study of hidden paint layers, which applies to the oeuvre of Van Gogh in particular and to old master paintings in general.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000258448100039 Publication Date 2008-07-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 178 Open Access
Notes Approved (down) Most recent IF: 6.32; 2008 IF: 5.712
Call Number UA @ admin @ c:irua:74466 Serial 5906
Permanent link to this record
 
 
Author Bings, N.H.; Bogaerts, A.; Broekaert, J.A.C.
Title Atomic spectroscopy Type A1 Journal article
Year 2006 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 78 Issue 12 Pages 3917-3945
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000238252600007 Publication Date 2006-06-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 112 Open Access
Notes Approved (down) Most recent IF: 6.32; 2006 IF: 5.646
Call Number UA @ lucian @ c:irua:60058 Serial 192
Permanent link to this record
 
 
Author Bulska, E.; Wysocka, I.A.; Wierzbicka, M.H.; Proost, K.; Janssens, K.; Falkenberg, G.
Title In vivo investigation of the distribution and the local speciation of selenium in Allium cepa L. by means of microscopic X-ray absorption near-edge structure spectroscopy and confocal microscopic X-ray fluorescence analysis Type A1 Journal article
Year 2006 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 78 Issue 22 Pages 7616-7624
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000242021400003 Publication Date 2006-10-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 56 Open Access
Notes Approved (down) Most recent IF: 6.32; 2006 IF: 5.646
Call Number UA @ admin @ c:irua:60714 Serial 5659
Permanent link to this record
 
 
Author Bings, N.H.; Bogaerts, A.; Broekaert, J.A.C.
Title Atomic spectroscopy Type A1 Journal article
Year 2004 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 76 Issue 12 Pages 3313-3336
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000222011100006 Publication Date 2004-06-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 32 Open Access
Notes Approved (down) Most recent IF: 6.32; 2004 IF: 5.450
Call Number UA @ lucian @ c:irua:46258 Serial 193
Permanent link to this record
 
 
Author Adriaensen, L.; Vangaever, F.; Gijbels, R.
Title Metal-assisted secondary ion mass spectrometry: the influence of Ag and Au deposition on molecular ion yields Type A1 Journal article
Year 2004 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 76 Issue 22 Pages 6777-6785
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000225076400033 Publication Date 2004-11-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 67 Open Access
Notes Approved (down) Most recent IF: 6.32; 2004 IF: 5.450
Call Number UA @ lucian @ c:irua:51980 Serial 2006
Permanent link to this record
 
 
Author Bings, N.H.; Bogaerts, A.; Broekaert, J.A.C.
Title Atomic spectroscopy Type A1 Journal article
Year 2002 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 74 Issue 12 Pages 2691-2712
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000176253700006 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 18 Open Access
Notes Approved (down) Most recent IF: 6.32; 2002 IF: 5.094
Call Number UA @ lucian @ c:irua:40192 Serial 194
Permanent link to this record
 
 
Author Kempenaers, L.; Janssens, K.; Vincze, L.; Vekemans, B.; Somogyi, A.; Drakopoulos, M.; Simionovici, A.S.; Adams, F.
Title A Monte Carlo model for studying the microheterogeneity of trace elements in reference materials by means of synchrotron microscopic X-ray fluorescence Type A1 Journal article
Year 2002 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 74 Issue 19 Pages 5017-5026
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000178418100031 Publication Date 2002-09-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 21 Open Access
Notes Approved (down) Most recent IF: 6.32; 2002 IF: 5.094
Call Number UA @ admin @ c:irua:39871 Serial 5734
Permanent link to this record
 
 
Author Vincze, L.; Somogyi, A.; Osán, J.; Vekemans, B.; Török, S.; Janssens, K.; Adams, F.
Title Quantitative trace element analysis of individual fly ash particles by means of X-ray microfluorescence Type A1 Journal article
Year 2002 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 74 Issue Pages 1128-1135
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000174187900032 Publication Date 2006-06-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 44 Open Access
Notes Approved (down) Most recent IF: 6.32; 2002 IF: 5.094
Call Number UA @ admin @ c:irua:38377 Serial 5796
Permanent link to this record
 
 
Author Gregory, C.L.; Nullens, H.A.; Gijbels, R.H.; van Espen, P.J.; Geuens, I.; de Keyzer, R.
Title Automated particle analysis of populations of silver halide microcrystals by electron probe microanalysis under cryogenic conditions Type A1 Journal article
Year 1998 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 70 Issue Pages 2551-2559
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Chemometrics (Mitac 3)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000074584700047 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 12 Open Access
Notes Approved (down) Most recent IF: 6.32; 1998 IF: 4.580
Call Number UA @ lucian @ c:irua:21308 Serial 210
Permanent link to this record
 
 
Author Poels, K.; van Vaeck, L.; Gijbels, R.
Title Microprobe speciation analysis of inorganic solids by Fourier transform laser mass spectrometry Type A1 Journal article
Year 1998 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 70 Issue Pages 504-512
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000071810400012 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 32 Open Access
Notes Approved (down) Most recent IF: 6.32; 1998 IF: 4.580
Call Number UA @ lucian @ c:irua:19338 Serial 2026
Permanent link to this record
 
 
Author Verlinden, G.; Janssens, G.; Gijbels, R.; van Espen, P.; Geuens, I.
Title Three-dimensional chemical characterization of complex silver halide microcrystals by scanning ion microprobe mass analysis Type A1 Journal article
Year 1997 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 69 Issue Pages 3773-3779
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Chemometrics (Mitac 3)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos A1997XV71200019 Publication Date 2002-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700;1520-6882; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 6 Open Access
Notes Approved (down) Most recent IF: 6.32; 1997 IF: 4.743
Call Number UA @ lucian @ c:irua:16959 Serial 3647
Permanent link to this record
 
 
Author Vanschoenwinkel, J.; Mendelsohn, R.; Van Passel, S.
Title Do Western and Eastern Europe have the same agricultural climate response? Taking adaptive capacity into account Type A1 Journal article
Year 2016 Publication Global Environmental Change-Human And Policy Dimensions Abbreviated Journal Global Environ Chang
Volume 41 Issue Pages 74-87
Keywords A1 Journal article; Economics; Engineering Management (ENM)
Abstract Current cross-sectional methodologies measuring climate change impacts assume that regions at the same latitude face a similar climate response and therefore have the same adaptive capacity. This paper proves that assumption to be erroneous in the European Union. It does so by ameliorating the Ricardian methodology by restricting which farmers (and therefore which adaptation options) are allowed in the dataset. In doing so, a comparative Ricardian methodology is suggested that makes it possible to examine, for the first time, how the climate responsiveness of a region changes if adaptive capacity changes. The paper combines climate, soil, geographic, socio-economic, and farm-level data in a linear mixed-effect model and examines whether Eastern and Western Europe have the same climate responses and how these responses change if regional adaptive capacity increases. The paper concludes that both regions currently have a significantly different climate response, but that if Eastern Europe were to implement the same adaptation options as Western Europe, it could avoid a large decrease in land value and even benefit from climate change depending on the climate scenario.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000389732700007 Publication Date 2016-09-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-3780; 1872-9495 ISBN Additional Links UA library record; WoS full record; WoS citing articles; WoS full record; WoS citing articles
Impact Factor 6.327 Times cited 8 Open Access
Notes ; Steven Van Passel would kindly want to express his gratitude towards DG AGRI for access to the Farm Accountancy Data Network (FADN). The authors also thank the reviewers of this journal for their improvements to the final manuscript and they are grateful for the comments and suggestions they received at the conferences where this paper has been presented (IAMO forum 2015, EAAE PhD workshop 2015, Belgian PhD symposium 2015, EAERE conference 2016). Janka Vanschoenwinkel also wants to thank FWO and the Doctoral Schools of Hasselt University for giving a mobility grant to go to the EAAE PhD workshop in Rome. ; Approved (down) Most recent IF: 6.327
Call Number UA @ admin @ c:irua:139026 Serial 6185
Permanent link to this record
 
 
Author Aghaei, M.; Lindner, H.; Bogaerts, A.
Title Ion Clouds in the Inductively Coupled Plasma Torch: A Closer Look through Computations Type A1 Journal article
Year 2016 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 88 Issue 88 Pages 8005-8018
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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.
Address Research Group PLASMANT, Chemistry Department, University of Antwerp , Universiteitsplein 1, 2610 Antwerp, Belgium
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Wos 000381654800020 Publication Date 2016-07-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 9 Open Access
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 (down) Most recent IF: 6.32
Call Number PLASMANT @ plasmant @ c:irua:135644 Serial 4293
Permanent link to this record
 
 
Author Rahemi, V.; Sarmadian, N.; Anaf, W.; Janssens, K.; Lamoen, D.; Partoens, B.; De Wael, K.
Title Unique opto-electronic structure and photo reduction properties of sulfur doped lead chromates explaining their instability in paintings Type A1 Journal article
Year 2017 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 89 Issue 89 Pages 3326-3334
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Chrome yellow refers to a group of synthetic inorganic pigments that became popular as an artists material from the second quarter of the 19th century. The color of the pigment, in which the chromate ion acts as a chromophore, is related to its chemical composition (PbCr1-xSxO4, with 0≤x≤0.8) and crystalline structure (monoclinic/orthorhombic). Their shades range from the yellow-orange to the paler yellow tones with increasing sulfate amount. These pigments show remarkable signs of degradation after limited time periods. Pure PbCrO4 (crocoite in its natural form) has a deep yellow color and is relatively stable, while the co-precipitate with lead sulfate (PbCr1-xSxO4) has a paler shade and seems to degrade faster. This degradation is assumed to be related to the reduction of Cr(VI) to Cr(III). We show that on increasing the sulfur(S)-content in chrome yellow, the band gap increases. Typically, when increasing the band gap, one might assume that a decrease in photo activity is the result. However, the photo activity relative to the Cr content, and thus Cr reduction, of sulfur-rich PbCr1-xSxO4 is found to be much higher compared to the sulfur-poor or non-doped lead chromates. This discrepancy can be explained by the evolution of the crystal and electronic structure as function of the sulfur content: first-principles density functional theory calculations show that both the absorption coefficient and reflection coefficients of the lead chromates change as a result of the sulfate doping in such a way that the generation of electron-hole pairs under illumination relative to the total Cr content increases. These changes in the material properties explain why paler shade yellow colors of this pigment are more prone to discoloration. The electronic structure calculations also demonstrate that lead chromate and its co-precipitates are p-type semiconductors, which explains the observed reduction reaction. As understanding this phenomenon is valuable in the field of cultural heritage, this study is the first joint action of photo-electrochemical measurements and first-principles calculations to approve the higher tendency of sulfur-rich lead chromates to darken.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000397478300015 Publication Date 2017-02-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 7 Open Access OpenAccess
Notes ; The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the Hercules Foundation and the Flemish Government, department EWI. The BOF-GOA action SOLARPAINT of the University of Antwerp Research Council is acknowledged for financial support. W.A. acknowledges support from BELSPO project S2-ART. Dr. L. Monico and Dr. C. Miliani (ISTM, Perugia) are gratefully acknowledged for helpful discussions and for providing some of the initial batches of the materials studied. ; Approved (down) Most recent IF: 6.32
Call Number UA @ lucian @ c:irua:140886 Serial 4451
Permanent link to this record
 
 
Author Fuchs, J.; Aghaei, M.; Schachel, T.D.; Sperling, M.; Bogaerts, A.; Karst, U.
Title Impact of the Particle Diameter on Ion Cloud Formation from Gold Nanoparticles in ICPMS Type A1 Journal article
Year 2018 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 90 Issue 17 Pages 10271-10278
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000444060600028 Publication Date 2018-09-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 5 Open Access OpenAccess
Notes We thank Dr. Harald Rösner from the Institute of Materials Physics of the University of Münster for the TEM imaging. Approved (down) Most recent IF: 6.32
Call Number PLASMANT @ plasmant @c:irua:153651 Serial 5057
Permanent link to this record
 
 
Author Gorbanev, Y.; Privat-Maldonado, A.; Bogaerts, A.
Title Analysis of Short-Lived Reactive Species in Plasma–Air–Water Systems: The Dos and the Do Nots Type A1 Journal Article
Year 2018 Publication Analytical Chemistry Abbreviated Journal Anal Chem
Volume 90 Issue 22 Pages 13151-13158
Keywords A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000451246100002 Publication Date 2018-11-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 17 Open Access Not_Open_Access
Notes European Commission, 743151 ; This work was supported by the European Marie Sklodowska- Curie Individual Fellowship within Horizon2020 (“LTPAM”, Grant No. 743151). Approved (down) Most recent IF: 6.32
Call Number PLASMANT @ plasmant @c:irua:156301 Serial 5152
Permanent link to this record
 
 
Author Sleegers, N.; van Nuijs, A.L.N.; van den Berg, M.; De Wael, K.
Title Cephalosporin antibiotics : electrochemical fingerprints and core structure reactions investigated by LC-MSMS Type A1 Journal article
Year 2019 Publication Analytical chemistry Abbreviated Journal Anal Chem
Volume 91 Issue 3 Pages 2035-2041
Keywords A1 Journal article; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre
Abstract Electrochemistry and exploiting electrochemical fingerprints is a potent approach to address newly emerging surveillance needs, for instance for antibiotics. However, a comprehensive insight in the electrochemical oxidation behaviour and mechanism is re-quired for this sensing strategy. To address the lack in knowledge of the voltammetric behaviour of the cephalosporins antibiotics, a selection of cephalosporin antibiotics and two main intermediates were subjected to an electrochemical study of their redox behaviour by means of pulsed voltammetric techniques and small-scale electrolysis combined with HPLC-MS/MS analyses. Sur-prisingly, the detected oxidation products did not fit the earlier suggested oxidation of the sulfur group to the corresponding sul-foxide. The influence of different side chains, both at the three and the seven position of the β-lactam core structure on the elec-trochemical fingerprint were investigated. Additional oxidation signals at lower potentials were elucidated and linked to different side chains. These signals were further exploited to allow simultaneous detection of different cephalosporins in one voltammetric sweep. These fundamental insights can become the building blocks for an new on-site screening method.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000458220300055 Publication Date 2019-01-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.32 Times cited 6 Open Access
Notes ; The authors acknowledge financial support from the Fund for Scientific Research (FWO) Flanders, Grant 1S 37658 17N. ; Approved (down) Most recent IF: 6.32
Call Number UA @ admin @ c:irua:156046 Serial 5497
Permanent link to this record