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“Single-particle analysis of aerosols at Cheju Island, Korea, using low-Z electron probe X-ray microanalysis: a direct proof of nitrate formation from sea salts”. Ro C-U, Oh K-Y, Kim H, Kim YP, Lee CB, Kim K-H, Kang CH, Osán J, de Hoog J, Worobiec A, Van Grieken R, Environmental science and technology 35, 4487 (2001). http://doi.org/10.1021/ES0155231
Keywords: A1 Journal article; Laboratory Experimental Medicine and Pediatrics (LEMP); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/ES0155231
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“Heterogeneity assessment in individual CaCO3-CaSO4 particles using ultrathin window electron probe X-ray microanalysis”. Ro C-U, Oh K-Y, Osán J, de Hoog J, Worobiec A, Van Grieken R, Analytical chemistry 73, 4574 (2001). http://doi.org/10.1021/AC010438X
Keywords: A1 Journal article; Laboratory Experimental Medicine and Pediatrics (LEMP); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC010438X
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“Electrochemical analysis of cocaine in real samples based on electrodeposited biomimetic affinity ligands”. Florea A, Cowen T, Piletsky S, De Wael K, The analyst 144, 4639 (2019). http://doi.org/10.1039/C9AN00618D
Abstract: A selective electrochemical sensor for direct detection of cocaine was developed based on molecularly imprinted polymers electropolymerized onto graphene-modified electrodes. Palladium nanoparticles were integrated in the sensing layer for the benefit of enhancing the communication between imprinted sites and electrode and improving their homogenous distribution. The molecularly imprinted polymer was synthesized by cyclic voltammetry using p-aminobenzoic acid as high affinity monomer selected by computational modeling, and cocaine as template molecule. Experimental parameters related to the electrochemical deposition of palladium nanoparticles, pH, composition of electropolymerization mixture, extraction and rebinding condition were studied and optimized. Under optimized conditions the oxidation peak current varied linearly with cocaine concentration in the range of 100-500 µM, with a detection limit of 50 µM (RSD 0.71%, n=3). The molecularly imprinted sensor was able to detect cocaine in saliva and river water with good recoveries after sample pretreatment and was successfully applied for screening real street samples for cocaine.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.885
Times cited: 3
DOI: 10.1039/C9AN00618D
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“Unraveling the effect of the aptamer complementary element on the performance of duplexed aptamers : a thermodynamic study”. Dillen A, Vandezande W, Daems D, Lammertyn J, Analytical And Bioanalytical Chemistry 413, 4739 (2021). http://doi.org/10.1007/S00216-021-03444-Y
Abstract: Duplexed aptamers (DAs) are widespread aptasensor formats that simultaneously recognize and signal the concentration of target molecules. They are composed of an aptamer and aptamer complementary element (ACE) which consists of a short oligonucleotide that partially inhibits the aptamer sequence. Although the design principles to engineer DAs are straightforward, the tailored development of DAs for a particular target is currently based on trial and error due to limited knowledge of how the ACE sequence affects the final performance of DA biosensors. Therefore, we have established a thermodynamic model describing the influence of the ACE on the performance of DAs applied in equilibrium assays and demonstrated that this relationship can be described by the binding strength between the aptamer and ACE. To validate our theoretical findings, the model was applied to the 29-mer anti-thrombin aptamer as a case study, and an experimental relation between the aptamer-ACE binding strength and performance of DAs was established. The obtained results indicated that our proposed model could accurately describe the effect of the ACE sequence on the performance of the established DAs for thrombin detection, applied for equilibrium assays. Furthermore, to characterize the binding strength between the aptamer and ACEs evaluated in this work, a set of fitting equations was derived which enables thermodynamic characterization of DNA-based interactions through thermal denaturation experiments, thereby overcoming the limitations of current predictive software and chemical denaturation experiments. Altogether, this work encourages the development, characterization, and use of DAs in the field of biosensing.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.431
DOI: 10.1007/S00216-021-03444-Y
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“Rapid microwave synthesis of high aspect-ration ZnO nanotetrapods for swift bisphenol A detection”. Qurashi A, Rather JA, De Wael K, Merzougui B, Tabet N, Faiz M, The analyst 138, 4764 (2013). http://doi.org/10.1039/C3AN00336A
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.885
Times cited: 15
DOI: 10.1039/C3AN00336A
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“Single-particle characterization of urban aerosol particles collected in three Korean cities using low-Z electron probe x-ray microanalysis”. Ro C-U, Kim H, Oh K-Y, Yea SK, Lee CB, Jang M, Van Grieken R, Environmental science and technology 36, 4770 (2002). http://doi.org/10.1021/ES025697Y
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/ES025697Y
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“Large-area elemental imaging reveals Van Eyck's original paint layers on the Ghent altarpiece (1432), rescoping its conservation treatment”. van der Snickt G, Dubois H, Sanyova J, Legrand S, Coudray A, Glaude C, Postec M, van Espen P, Janssens K, Angewandte Chemie: international edition in English 56, 4797 (2017). http://doi.org/10.1002/ANIE.201700707
Abstract: A combination of large-scale and micro-scale elemental imaging, yielding elemental distribution maps obtained by, respectively non-invasive macroscopic X-ray fluorescence (MA-XRF) and by secondary electron microscopy/energy dispersive X-ray analysis (SEM-EDX) and synchrotron radiation-based micro-XRF (SR m-XRF) imaging was employed to reorient and optimize the conservation strategy of van Eyck's renowned Ghent Altarpiece. By exploiting the penetrative properties of X-rays together with the elemental specificity offered by XRF, it was possible to visualize the original paint layers by van Eyck hidden below the overpainted surface and to simultaneously assess their condition. The distribution of the high-energy Pb-L and Hg-L emission lines revealed the exact location of hidden paint losses, while Fe-K maps demonstrated how and where these lacunae were filled-up using an iron-containing material. The chemical maps nourished the scholarly debate on the overpaint removal with objective, chemical arguments, leading to the decision to remove all skillfully applied overpaints, hitherto interpreted as work by van Eyck. MA-XRF was also employed for monitoring the removal of the overpaint during the treatment phase. To gather complementary information on the in-depth layer build-up, SEM-EDX and SR mu-XRF imaging was used on paint cross sections to record microscale elemental maps.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 11.994
Times cited: 11
DOI: 10.1002/ANIE.201700707
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“Towards developing a screening strategy for ecstasy : revealing the electrochemical profile”. Thiruvottriyur Shanmugam S, Van Echelpoel R, Boeye G, Eliaerts J, Samanipour M, Ching HYV, Florea A, Van Doorslaer S, Van Durme F, Samyn N, Parrilla M, De Wael K, Chemelectrochem 8, 4826 (2021). http://doi.org/10.1002/CELC.202101198
Abstract: This article describes the development of an electrochemical screening strategy for 3,4-methylenedioxymethamphetamine (MDMA), the regular psychoactive compound in ecstasy (XTC) pills. We have investigated the specific electrochemical profile of MDMA and its electro-oxidation mechanisms at disposable graphite screen-printed electrodes. We have proved that the formation of a radical cation and subsequent reactions are indeed responsible for the electrode surface passivation, as evidenced by using electron paramagnetic resonance spectroscopy and electrochemistry. Thereafter, pure cutting agents and MDMA as well as simulated binary mixtures of compounds with MDMA were subjected to square wave voltammetry at pH 7 to understand the characteristic electrochemical profile. An additional measurement at pH 12 was able to resolve false positives and negatives occurring at pH 7. Finally, validation of the screening strategy was done by measuring a set of ecstasy street samples. Overall, our proposed electrochemical screening strategy has been demonstrated for the rapid, sensitive, and selective detection of MDMA, resolving most of the false positives and negatives given by the traditional Marquis color tests, thus exhibiting remarkable promises for the on-site screening of MDMA.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Organic synthesis (ORSY); Applied Electrochemistry & Catalysis (ELCAT); Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Impact Factor: 4.136
DOI: 10.1002/CELC.202101198
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“The use of potentiometric sensors to study (bio)molecular interactions”. De Wael K, Daems D, Van Camp G, Nagels LJ, Analytical chemistry 84, 4921 (2012). http://doi.org/10.1021/AC3005428
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.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 10
DOI: 10.1021/AC3005428
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“Chemical speciation of individual atmospheric particles using low-Z electron probe X-ray microanalysis characterizing “Asian Dust&rdquo, deposited with rainwater in Seoul, Korea”. Ro C-U, Oh K-Y, Kim HK, Chun Y, Osán J, de Hoog J, Van Grieken R, Atmospheric environment : an international journal 35, 4995 (2001). http://doi.org/10.1016/S1352-2310(01)00287-4
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/S1352-2310(01)00287-4
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“Electrochemical sensing of phenicol antibiotics at gold”. Pilehvar S, Dardenne F, Blust R, De Wael K, International journal of electrochemical science 7, 5000 (2012)
Abstract: Phenicols are an effective and a broad spectrum class of antibiotics which has lost favour due to their side effects on human health. A rapid and sensitive electrochemical detection system is developed for the simultaneous detection of chloramphenicol (CAP), thiamphenicol (TAP) and florfenicol (FF). The electrochemical behaviour of CAP in the presence of its derivatives was investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV). At a gold electrode, CAP gives rise to a sensitive cathodic peak at −0.68V (versus SCE) in a tris buffer solution (pH 7.6). This behavior gives us the opportunity to introduce a method for sensing CAP electrochemically in the presence of its derivatives. Calibration graphs were linear in the 2.5-7.4 μmol L-1 concentration range. Deviations from linearity were observed for higher concentrations and this was interpreted to be due to kinetic limitation caused by the saturation of CAP and its reduction products onto the gold electrode surface. A limit of detection of 1 μmol L-1 was found.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.469
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“Atmospheric turbulence triggers pronounced diel pattern in karst carbonate geochemistry”. Roland M, Serrano-Ortiz P, Kowalski AS, Van Grieken R, Janssens IA, et al, Biogeosciences 10, 5009 (2013). http://doi.org/10.5194/BG-10-5009-2013
Abstract: CO2 exchange between terrestrial ecosystems and the atmosphere is key to understanding the feedbacks between climate change and the land surface. In regions with carbonaceous parent material, CO2 exchange patterns occur that cannot be explained by biological processes, such as disproportionate outgassing during the daytime or night-time CO2 uptake during periods when all vegetation is senescent. Neither of these phenomena can be attributed to carbonate weathering reactions, since their CO2 exchange rates are too small. Soil ventilation induced by high atmospheric turbulence is found to explain atypical CO2 exchange between carbonaceous systems and the atmosphere. However, by strongly altering subsurface CO2 concentrations, ventilation can be expected to influence carbonate weathering rates. By imposing ventilation-driven CO2 outgassing in a carbonate weathering model, we show here that carbonate geochemistry is accelerated and does play a surprisingly large role in the observed CO2 exchange pattern of a semi-arid ecosystem. We found that by rapidly depleting soil CO2 during the daytime, ventilation disturbs soil carbonate equilibria and therefore strongly magnifies daytime carbonate precipitation and associated CO2 production. At night, ventilation ceases and the depleted CO2 concentrations increase steadily. Dissolution of carbonate is now enhanced, which consumes CO2 and largely compensates for the enhanced daytime carbonate precipitation. This is why only a relatively small effect on global carbonate weathering rates is to be expected. On the short term, however, ventilation has a drastic effect on synoptic carbonate weathering rates, resulting in a pronounced diel pattern that exacerbates the non-biological behavior of soil-atmosphere CO2 exchanges in dry regions with carbonate soils.
Keywords: A1 Journal article; Plant and Ecosystems (PLECO) – Ecology in a time of change; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.5194/BG-10-5009-2013
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“A Monte Carlo model for studying the microheterogeneity of trace elements in reference materials by means of synchrotron microscopic X-ray fluorescence”. Kempenaers L, Janssens K, Vincze L, Vekemans B, Somogyi A, Drakopoulos M, Simionovici AS, Adams F, Analytical chemistry 74, 5017 (2002). http://doi.org/10.1021/AC025662G
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 21
DOI: 10.1021/AC025662G
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“Grazing-exit particle-induced X-ray emission analysis with extremely low background”. Tsuji K, Spolnik Z, Wagatsuma K, Van Grieken RE, Vis RD, Analytical chemistry 71, 5033 (1999). http://doi.org/10.1021/AC990568U
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC990568U
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“Levamisole : a common adulterant in cocaine street samples hindering electrochemical detection of cocaine”. De Jong M, Florea A, de Vries A-M, van Nuijs ALN, Covaci A, Van Durme F, Martins JC, Samyn N, De Wael K, Analytical chemistry 90, 5290 (2018). http://doi.org/10.1021/ACS.ANALCHEM.8B00204
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.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre
Impact Factor: 6.32
Times cited: 8
DOI: 10.1021/ACS.ANALCHEM.8B00204
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“Characterization of the atmospheric aerosol over the eastern equatorial Pacific”. Maenhaut W, Raemdonck H, Selen A, Van Grieken R, Winchester JW, Journal of geophysical research 88, 5353 (1983). http://doi.org/10.1029/JC088IC09P05353
Abstract: By using a polyester sailboat as sampling platform, a series of duplicate aerosol samples was collected by cascade impactors on a trip from Panama to Tahiti in 1979. Elemental analysis mainly by particle-induced X ray emission (PIXE) indicated, in the samples collected between Panama and the Galapagos Islands, the presence of a substantial crustal component (∼0.4 μg/m3), fine Cu (∼0.4 ng/m3) and Zn (∼0.6 ng/m3), and excess fine S and K (∼100 and ∼2.4 ng/m3, respectively) in addition to the major sea salt elements. The crustal component and fine Cu and Zn are suggested to result from natural continental sources (i.e., eolian dust transport from the American continents and perhaps geothermal emissions). Samples collected west of the Galapagos Islands in the southern trades showed significantly lower concentrations for the nonseawater components. The average Si and Fe levels were as low as 4.8 and 3.3 ng/m3, corresponding to a maximum of 0.066 μg/m3 for an assumed mineral dust component, whereas heavy metal concentrations were all below the detection limits (typically ranging from 0.05 to 0.15 ng/m3 for V, Cr, Mn, Ni, Cu, Zn, and Se). Excess fine S decreased to a mean of 46 ng/m3, a level similar to those reported for other remote marine and continental locations. This all indicates that the marine atmosphere west of the Galapagos was little influenced by natural continental source processes or by anthropogenic emissions. Under these truly marine conditions, several concentration ratios of the major seawater elements were significantly different from those in bulk seawater. Ca, Sr, and S in >1 μm diameter particles were enriched relative to K and Na, with the enrichment being substantially more pronounced (up to 50% or higher) for l4-μm diameter particles than for particles >4 μm. Comparison of these data with a similar data set from samples collected over the Atlantic indicates that the departures from seawater composition are significantly larger for the Pacific. Differences in sea-to-air fractionation processes, probably involving binding of divalent cations to organic matter in the oceanic surface microlayer, are suggested as being responsible for these observations.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1029/JC088IC09P05353
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“Division of labor and growth during electrical cooperation in multicellular cable bacteria”. Geerlings NMJ, Karman C, Trashin S, As KS, Kienhuis MVM, Hidalgo-Martinez S, Vasquez-Cardenas D, Boschker HTS, De Wael K, Middelburg JJ, Polerecky L, Meysman FJR, Proceedings Of The National Academy Of Sciences Of The United States Of America 117, 5478 (2020). http://doi.org/10.1073/PNAS.1916244117
Abstract: Multicellularity is a key evolutionary innovation, leading to coordinated activity and resource sharing among cells, which generally occurs via the physical exchange of chemical compounds. However, filamentous cable bacteria display a unique metabolism in which redox transformations in distant cells are coupled via long-distance electron transport rather than an exchange of chemicals. This challenges our understanding of organismal functioning, as the link among electron transfer, metabolism, energy conservation, and filament growth in cable bacteria remains enigmatic. Here, we show that cells within individual filaments of cable bacteria display a remarkable dichotomy in biosynthesis that coincides with redox zonation. Nanoscale secondary ion mass spectrometry combined with 13 C (bicarbonate and propionate) and 15 N-ammonia isotope labeling reveals that cells performing sulfide oxidation in deeper anoxic horizons have a high assimilation rate, whereas cells performing oxygen reduction in the oxic zone show very little or no label uptake. Accordingly, oxygen reduction appears to merely function as a mechanism to quickly dispense of electrons with little to no energy conservation, while biosynthesis and growth are restricted to sulfide-respiring cells. Still, cells can immediately switch roles when redox conditions change, and show no differentiation, which suggests that the “community service” performed by the cells in the oxic zone is only temporary. Overall, our data reveal a division of labor and electrical cooperation among cells that has not been seen previously in multicellular organisms.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 11.1
Times cited: 6
DOI: 10.1073/PNAS.1916244117
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“Quantitative determination of low-Z elements in single atmospheric particles on boron substrates by automated scanning electron microscopy: energy-dispersive X-ray spectrometry”. Choël M, Deboudt K, Osán J, Flament P, Van Grieken R, Analytical chemistry 77, 5686 (2005). http://doi.org/10.1021/AC050739X
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC050739X
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“Seasonal trends of atmospheric nitrogen dioxide and sulfur dioxide over North Santa Clara, Cuba”. Alejo D, Morales MC, de la Torre JB, Grau R, Bencs L, Van Grieken R, van Espen P, Sosa D, Nuñez V, Environmental monitoring and assessment 185, 6023 (2013). http://doi.org/10.1007/S10661-012-3003-4
Abstract: Atmospheric nitrogen dioxide (NO2) and sulfur dioxide (SO2) levels were monitored simultaneously by means of Radiello passive samplers at six sites of Santa Clara city, Cuba, in the cold and the warm seasons in 2010. The dissolved ionic forms of NO2 and SO2 as nitrate and sulfite plus sulfate, respectively, were determined by means of ion chromatography. Analysis of NO2 as nitrite was also performed by UVVis spectrophotometry. For NO2, significant t tests show good agreement between the results of IC and UVVis methods. The NO2 and SO2 concentrations peaked in the cold season, while their minimum levels were experienced in the warm season. The pollutant levels do not exceed the maximum allowable limit of the Cuban Standard 39:1999, i.e., 40 μg/m3 and 50 μg/m3 for NO2 and SO2, respectively. The lowest pollutant concentrations obtained in the warm season can be attributed to an increase in their removal via precipitation (scavenging) while to the decreased traffic density and industrial emission during the summer holidays (e.g., July and August).
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S10661-012-3003-4
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“Synthesis and characterization of heteroleptic rare earth double-decker complexes involving tetradiazepinoporphyrazine and phthalocyanine macrocycles”. Tarakanova EN, Tarakanov PA, Simakov AO, Furuyama T, Kobayashi N, Konev DV, Goncharova OA, Trashin SA, De Wael K, Sulimenkov IV, Filatov VV, Kozlovskiy VI, Tomilova LG, Stuzhin PA, Pushkarev VE, Dalton Transactions 50, 6245 (2021). http://doi.org/10.1039/D1DT00088H
Abstract: Reaction of (2,3,9,10,16,17,23,24-octabutylphthalocyaninato)lanthanide(iii) acetylacetonates ((Bu)PcLn(acac), 1a-c, Ln = Lu (a), Eu (b), La (c)) with a tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazine ligand ((tBuPh)DzPzH(2), 2) produced sandwich compounds ((tBuPh)DzPz)Ln(Pc-Bu) (3a-c), which represent the first heteroleptic double-deckers incorporating both Pc and DzPz decks. A combination of high-resolution mass spectrometry, UV-Vis/NIR, MCD, and H-1 NMR spectroscopy, and square-wave voltammetry provided unambiguous characterization of target complexes 3 indicating that their spectral and electrochemical properties are generally intermediate with respect to their homoleptic relatives. Based on the data of solution-state H-1-H-1 NMR (COSY, NOESY) correlation spectroscopy supported by DFT calculations, a dimerization tendency of compounds 3 proportional to the Ln(iii) ion size was found. The spectroelectrochemical study of 3 and the corresponding homoleptic double-deckers revealed a pronounced tendency to aggregation of the one-electron oxidized forms of DzPz-containing double-decker complexes compared to homoleptic Pc(2)Ln compounds.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.029
DOI: 10.1039/D1DT00088H
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“Copper stabilization by zeolite synthesis in polluted soils treated with coal fly ash”. Terzano R, Spagnuolo M, Medici L, Vekemans B, Vincze L, Janssens K, Ruggiero P, Environmental science and technology 39, 6280 (2005). http://doi.org/10.1021/ES050079D
Abstract: This study deals with the process of zeolite formation in an agricultural soil artificially polluted by high amounts of Cu (15 mg of Cu/g of soil dry weight) and treated with fused coal fly ash at 30 and 60 degrees C and how this process affects the mobility and availability of the metal. As a consequence of the treatment, the amount of dissolved Cu, and thus its mobility, was strongly reduced, and the percentage of the metal stabilized in the solid phase increased over time, reaching values of 30% at 30 degrees C and 40% at 60 degrees C. The physicochemical phenomena responsible for Cu stabilization in the solid phase have been evaluated by EDTA sequential extractions and synchrotron radiation based X-ray microanalytical techniques. These techniques were used for the visualization of the spatial distribution and the speciation of Cu in and/or on the neo-formed zeolite particles. In particular, micro XRF (X-ray fluorescence) tomography showed direct evidence that Cu can be entrapped as clusters inside the porous zeolitic structures while,mu-XANES (X-ray absorption near edge structure) spectroscopy determinations revealed Cu to be present mainly as Cu(II) hydroxide and Cu(II) oxide. The reported results could be useful as a basic knowledge for planning new technologies for the on site physicochemical stabilization of heavy metals in heavily polluted soils.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.198
Times cited: 39
DOI: 10.1021/ES050079D
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“Determination of platinum, palladium, and rhodium in automotive catalysts using high-energy secondary target X-ray fluorescence spectrometry”. van Meel K, Smekens A, Behets M, Kazandjian P, Van Grieken R, Analytical chemistry 79, 6383 (2007). http://doi.org/10.1021/AC070815R
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC070815R
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“Macroscopic X-ray powder diffraction scanning, a new method for highly selective chemical imaging of works of art : instrument optimization”. Vanmeert F, de Nolf W, De Meyer S, Dik J, Janssens K, Analytical chemistry 90, 6436 (2018). http://doi.org/10.1021/ACS.ANALCHEM.8B00240
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.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 11
DOI: 10.1021/ACS.ANALCHEM.8B00240
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“Visualization of a lost painting by Vincent van Gogh using synchrotron radiation based X-ray fluorescence elemental mapping”. Dik J, Janssens K, van der Snickt G, van der Loeff L, Rickers K, Cotte M, Analytical chemistry 80, 6436 (2008). http://doi.org/10.1021/AC800965G
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.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 178
DOI: 10.1021/AC800965G
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“Macroscopic X-ray powder diffraction scanning : possibilities for quantitative and depth-selective parchment analysis”. Vanmeert F, de Nolf W, Dik J, Janssens K, Analytical chemistry 90, 6445 (2018). http://doi.org/10.1021/ACS.ANALCHEM.8B00241
Abstract: 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.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 6
DOI: 10.1021/ACS.ANALCHEM.8B00241
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“Methods, fluxes and sources of gas phase alkyl nitrates in the coastal air”. Dirtu AC, Buczyńska AJ, Godoi AFL, Favoreto R, Bencs L, Potgieter-Vermaak SS, Godoi RHM, Van Grieken R, Van Vaeck L, Environmental monitoring and assessment 186, 6445 (2014). http://doi.org/10.1007/S10661-014-3866-7
Abstract: The daily and seasonal atmospheric concentrations, deposition fluxes and emission sources of a few C3C9 gaseous alkyl nitrates (ANs) at the Belgian coast (De Haan) on the Southern North Sea were determined. An adapted sampler design for low- and high-volume air-sampling, optimized sample extraction and clean-up, as well as identification and quantification of ANs in air samples by means of gas chromatography mass spectrometry, are reported. The total concentrations of ANs ranged from 0.03 to 85 pptv and consisted primarily of the nitro-butane and nitro-pentane isomers. Air mass backward trajectories were calculated by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to determine the influence of main air masses on AN levels in the air. The shorter chain ANs have been the most abundant in the Atlantic/Channel/UK air masses, while longer chain ANs prevailed in continental air. The overall mean N fluxes of the ANs were slightly higher for summer than those for winter-spring, although their contributions to the total nitrogen flux were low. High correlations between AN and HNO2 levels were observed during winter/spring. During summer, the shorter chain ANs correlated well with precipitation. Source apportionment by means of principal component analysis indicated that most of the gas phase ANs could be attributed to traffic/combustion, secondary photochemical formation and biomass burning, although marine sources may also have been present and a contributing factor.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre
DOI: 10.1007/S10661-014-3866-7
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“Determination of the cd-bearing phases in municipal solid waste and Biomass single fly ash particles using SR-mu XRF Spectroscopy”. Camerani MC, Somogyi A, Vekemans B, Ansell S, Simionovici AS, Steenari B-M, Panas I, Analytical chemistry 79, 6496 (2007). http://doi.org/10.1021/AC070206J
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC070206J
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“Disclosing the binding medium effects and the pigment solubility in the (photo)reduction process of chrome yellows (PbCrO4/PbCr1-xSxO4)”. Monico L, Sorace L, Cotte M, de Nolf W, Janssens K, Romani A, Miliani C, ACS Omega 4, 6607 (2019). http://doi.org/10.1021/ACSOMEGA.8B03669
Abstract: The darkening due to chemical alteration of chrome yellows (PbCrO4/PbCr1-xSxO4) is a phenomenon threatening a large number of 19th-20th century paintings, including the Amsterdam Sunflowers by Vincent van Gogh. Our earlier studies have proven that the alteration is due to a Cr(VI) -> Cr(III) reduction with Cr(V)-species that are formed as long-lived intermediates and that bCr(1-x)S(x)O(4) (0 < x <= 0.8) types undergo reduction more readily than monoclinic, S-free, PbCrO4. In this context, there is still lack of knowledge about the effects of the chemical properties of the binding medium (i.e., chemical composition and drying process) and the solubility of chrome yellows on the overall reduction pathways. Here, we study a series of naturally and photochemically aged mock-up paints prepared by mixing chrome yellow powders (PbCrO4/PbCr0.2S0.8O4) with either linseed oil or a water-based acrylic emulsion as the binding medium. Equivalent paints made up of the highly soluble K2CrO4 were also investigated and used as benchmarks to provide a more in-depth understanding of the influence of the solubility on the chromate reduction pathways in the two different binders. A combination of synchrotron radiation-based Cr K-edge X-ray absorption near edge structure (XANES), electron paramagnetic resonance (EPR), and UV-Visible spectroscopy measurements shows that: (1) the Cr(VI) reduction results from the interaction between the pigment and the binder; (2) the process is more significant in oil, giving rise to Cr(V)- and Cr(III)-species as well as oxidized organic compounds; (3) the lightfastness of the chrome yellow pigment is enhanced in the acrylic binder; and (4) the tendency toward chromium reduction increases with increasing solubility of the pigment. Based on our findings, we propose a scheme for the mechanism of the (photo)reduction process of chrome yellows in the oil and acrylic binder. Overall, our results provide new insights into the factors driving the degradation of lead chromate-based paints in artworks and contribute to the development of strategies for preserving them over time.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 4
DOI: 10.1021/ACSOMEGA.8B03669
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“Aptasensing of chloramphenicol in the presence of its analogues : reaching the maximum residue limit”. Pilehvar S, Mehta J, Dardenne F, Robbens J, Blust R, De Wael K, Analytical chemistry 84, 6753 (2012). http://doi.org/10.1021/AC3012522
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.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 68
DOI: 10.1021/AC3012522
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“Real-time FO-SPR monitoring of solid-phase DNAzyme cleavage activity for cutting-edge biosensing”. Peeters B, Daems D, Van der Donck T, Delport F, Lammertyn J, ACS applied materials and interfaces 11, 6759 (2019). http://doi.org/10.1021/ACSAMI.8B18756
Abstract: DNA nanotechnology has a great potential in biosensor design including nanostructuring of the biosensor surface through DNA origami, target recognition by means of aptamers, and DNA-based signal amplification strategies. In this paper, we use DNA nanotechnology to describe for the first time the concept of real-time solid-phase monitoring of DNAzyme cleavage activity for the detection of specific single-stranded DNA (ssDNA) with a fiber optic surface plasmon resonance (FO-SPR) biosensor. Hereto, we first developed a robust ligation strategy for the functionalization of the FO-SPR biosensing surface with ssDNA-tethered gold nanoparticles, serving as the substrate for the DNAzyme. Next, we established a relation between the SPR signal change, due to the cleavage activity of the 10–23 DNAzyme, and the concentration of the DNAzyme, showing faster cleavage kinetics for higher DNAzyme concentrations. Finally, we implemented this generic concept for biosensing of ssDNA target in solution. Hereto, we designed a DNAzyme–inhibitor complex, consisting of an internal loop structure complementary to the ssDNA target, that releases active DNAzyme molecules in a controlled way as a function of the target concentration. We demonstrated reproducible target detection with a theoretical limit of detection of 1.4 nM, proving that the presented ligation strategy is key to a universal DNAzyme-based FO-SPR biosensing concept with promising applications in the medical and agrofood sector.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/ACSAMI.8B18756
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