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“A Monte Carlo program for quantitative electron-induced x-ray analysis of individual particles”. Ro C-U, Osán J, Szalóki I, de Hoog J, Worobiec A, Van Grieken R, Analytical chemistry 75, 851 (2003). http://doi.org/10.1021/AC025973R
Keywords: A1 Journal article; Laboratory Experimental Medicine and Pediatrics (LEMP); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC025973R
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“Nanobody-based immunosensor detection enhanced by photocatalytic-electrochemical redox cycling”. Trashin S, Morales-Yánez F, Thiruvottriyur Shanmugam S, Paredis L, Carrión EN, Sariego I, Muyldermans S, Polman K, Gorun SM, De Wael K, Analytical Chemistry 93, 13606 (2021). http://doi.org/10.1021/ACS.ANALCHEM.1C02876
Abstract: Detection of antigenic biomarkers present in trace amounts is of crucial importance for medical diagnosis. A parasitic disease, human toxocariasis, lacks an adequate diagnostic method despite its worldwide occurrence. The currently used serology tests may stay positive even years after a possibly unnoticed infection, whereas the direct detection of a re-infection or a still active infection remains a diagnostic challenge due to the low concentration of circulating parasitic antigens. We report a time-efficient sandwich immunosensor using small recombinant single-domain antibodies (nanobodies) derived from camelid heavy-chain antibodies specific to Toxocara canis antigens. An enhanced sensitivity to pg/mL levels is achieved by using a redox cycle consisting of a photocatalytic oxidation and electrochemical reduction steps. The photocatalytic oxidation is achieved by a photosensitizer generating singlet oxygen (1O2) that, in turn, readily reacts with p-nitrophenol enzymatically produced under alkaline conditions. The photooxidation produces benzoquinone that is electrochemically reduced to hydroquinone, generating an amperometric response. The light-driven process could be easily separated from the background, thus making amperometric detection more reliable. The proposed method for detection of the toxocariasis antigen marker shows superior performances compared to other detection schemes with the same nanobodies and outperforms by at least two orders of magnitude the assays based on regular antibodies, thus suggesting new opportunities for electrochemical immunoassays of challenging low levels of antigens.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Impact Factor: 6.32
DOI: 10.1021/ACS.ANALCHEM.1C02876
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“Parameter evaluation for the analysis of oxide-based samples with radio ferquency glow discharge mass spectrometry”. de Gendt S, Van Grieken RE, Ohorodnik SK, Harrison WW, Analytical chemistry 67, 1026 (1995). http://doi.org/10.1021/AC00102A002
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC00102A002
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“Particulate matter analysis at elementary schools in Curitiba, Brazil”. Avigo D, Godoi AFL, Janissek PR, Makarovska Y, Krata A, Potgieter-Vermaak S, Alfoldy B, Van Grieken R, Godoi RHM, Analytical and bioanalytical chemistry 391, 1459 (2008). http://doi.org/10.1007/S00216-008-2031-Y
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S00216-008-2031-Y
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“Performance of total reflection and grazing emission X-ray fluorescence spectrometry for the determination of trace metals in drinking water in relation to other analytical techniques”. Hołynska B, Olko M, Ostachowicz B, Ostachowicz J, Wegrzynek D, Claes M, Van Grieken R, de Bokx P, Kump P, Necemer M, Fresenius' journal of analytical chemistry 362, 294 (1998). http://doi.org/10.1007/S002160051077
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S002160051077
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“Possibilities of energy-resolved X-ray radiography for the investigation of paintings”. Cabal Rodríguez AE, Leyva Pernia D, Schalm O, van Espen PJM, Analytical and bioanalytical chemistry 402, 1471 (2012). http://doi.org/10.1007/S00216-011-5230-X
Abstract: X-ray radiographic images of paintings often show little or no contrast. In order to increase the contrast in radiographic images we measured the X-ray spectrum of a low power X-ray tube, after passing through the painting, with a high energy-resolution SDD detector. To obtain images, the detector is collimated with a 400 mu m diameter pinhole and the painting was moved through the beam in the x and y-direction using a dwell time of a few seconds per pixel. The data obtained consists of a data cube of, typically, 200 x 200 pixels and a 512-channel X-ray spectrum for each pixel, spanning the energy range from 0 to 40 keV. Having the absorbance spectrum available for each pixel, we are able, a posteriori, to produce images by edge subtraction for any given element. In this way high contrast, element-specific, images can be obtained. Because of the high energy-resolution a much simpler edge subtraction algorithm can be applied. We also used principal-component imaging to obtain, in a more automated way, images with high contrast. Some of these images can easily be attributed to specific elements. It turns out that preprocessing of the spectral data is crucial for the success of the multivariate image processing.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S00216-011-5230-X
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“Present and future applications of beam techniques in environmental microanalysis”. Jambers W, Van Grieken R, Trends in analytical chemistry 15, 114 (1996). http://doi.org/10.1016/0165-9936(95)00098-4
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/0165-9936(95)00098-4
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“Quantitative characterization of individual particle surfaces by fractal analysis of scanning electron microscope images”. van Put A, Vertes A, Wegrzynek D, Treiger B, Van Grieken R, Fresenius' journal of analytical chemistry 350, 440 (1994). http://doi.org/10.1007/BF00321787
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/BF00321787
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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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“Selenium in environmental waters : determination, speciation and concentration levels”. Robberecht H, Van Grieken R, Talanta : the international journal of pure and applied analytical chemistry 29, 823 (1982). http://doi.org/10.1016/0039-9140(82)80252-X
Abstract: This article reviews the different methods used for the determination of selenium species in all types of environmental waters. Basic difficulties are discussed and the efficiency of the methods is explained in view of the sub-μg/1. concentration levels. Special attention is paid to preconcentration steps. Published data on speciation and concentration levels in various water samples are critically reviewed.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/0039-9140(82)80252-X
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“Single-run ion chromatographic separation of inorganic and low-molecular-mass organic anions under isocratic elution: application to environmental samples”. Krata A, Kontozova-Deutsch V, Bencs L, Deutsch F, Van Grieken R, Talanta : the international journal of pure and applied analytical chemistry 79, 16 (2009). http://doi.org/10.1016/J.TALANTA.2009.02.044
Abstract: For the isocratic ion chromatography (IC) separation of low-molecular-mass organic acids and inorganic anions three different anion-exchange columns were studied: IonPac AS14 (9 ìm particle size), Allsep A-2 (7 ìm particle size), and IC SI-50 4E (5 ìm particle size). A complete baseline separation for all analyzed anions (i.e., F−, acetate, formate, Cl−, NO2−, Br−, NO3−, HPO42− and SO42−) in one analytical cycle of shorter than 17 min was achieved on the IC SI-50 4E column, using an eluent mixture of 3.2 mM Na2CO3 and 1.0 mM NaHCO3 with a flow rate of 1.0 mL min−1. On the IonPac AS14 column, it was possible to separate acetate from inorganic anions in one run (i.e., less than 9 min), but not formate, under the following conditions: 3.5 mM Na2CO3 plus 1.0 mM NaHCO3 with a flow rate of 1.2 mL min−1. Therefore, it was necessary to adapt a second run with a 2.0 mM Na2B4O7 solution as an eluent under a flow rate of 0.8 mL min−1 for the separation of organic ions, which considerably enlarged the analysis time. For the Allsep A-2 column, using an eluent mixture of 1.2 mM Na2CO3 plus 1.5 mM NaHCO3 with a flow rate of 1.6 mL min−1, it was possible to separate almost all anions in one run within 25 min, except the fluoride-acetate critical pair. A Certified Multianion Standard Solution PRIMUS for IC was used for the validation of the analytical methods. The lowest RSDs (less than 1%) and the best LODs (0.02, 0.2, 0.16, 0.11, 0.06, 0.05, 0.04, 0.14 and 0.09 mg L−1 for F−, Ac−, For−, Cl−, NO2−, Br−, NO3−, HPO42− and SO42−, respectively) were achieved using the IC SI-50 4E column. This column was applied for the separation of concerned ions in environmental precipitation samples such as snow, hail and rainwater.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/J.TALANTA.2009.02.044
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“Spark-source mass-spectrometric sensitivity factors for elements in a graphite matrix”. Vanderborght B, Van Grieken R, Talanta : the international journal of pure and applied analytical chemistry 26, 461 (1979). http://doi.org/10.1016/0039-9140(79)80111-3
Abstract: Relative sensitivity factors for determination of 41 elements by spark-source mass-spectrometry have been measured. The samples were pressed into graphite electrodes and ionized with a radiofrequency spark. The mass spectra were recorded on a photoplate and the resulting data processed by a computer. Indium was used as standard and the relative sensitivity factors for both singly- and doubly-charged ions were determined with reference to the singly-charged indium ion, with an overall error of 30%. The mean analysis precision was 16%.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/0039-9140(79)80111-3
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“Speciation of aerosols by combining bulk ion chromatography and thin-window electron probe micro analysis”. Eyckmans K, de Hoog J, van der Auwera L, Van Grieken R, International journal of environmental analytical chemistry 83, 777 (2003). http://doi.org/10.1080/0306731031000118934
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1080/0306731031000118934
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“Sub-part-per-billion determination of total dissolved selenium and selenite in environmental waters by X-ray fluorescence spectrometry”. Robberecht HJ, Van Grieken RE, Analytical chemistry 52, 449 (1980). http://doi.org/10.1021/AC50053A017
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC50053A017
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“Thin-layer potentiometry for creatinine detection in undiluted human urine using ion-exchange membranes as barriers for charged interferences”. Liu Y, Cánovas R, Crespo GA, Cuartero M, Analytical Chemistry 92, 3315 (2020). http://doi.org/10.1021/ACS.ANALCHEM.9B05231
Abstract: Herein, thin-layer potentiometry combined with ion-exchange membranes as barriers for charged interferences is demonstrated for the analytical detection of creatinine (CRE) in undiluted human urine. Briefly, CRE diffuses through an anion-exchange membrane (AEM) from a sample contained in one fluidic compartment to a second reservoir, containing the enzyme CRE deiminase. There, CRE reacts with the enzyme, and the formation of ammonium is dynamically monitored by potentiometric ammonium-selective electrodes. This analytical concept is integrated into a lab-on-a-chip microfluidic cell that allows for a high sample throughput and the operation under stop-flow mode, which allows CRE to passively diffuse across the AEM. Conveniently, positively charged species (i.e., potassium, sodium, and ammonium, among others) are repelled by the AEM and never reach the ammonium-selective electrodes; thus, possible interference in the response can be avoided. As a result, the dynamic potential response of the electrodes is entirely ascribed to the stoichiometric formation of ammonium. The new CRE biosensor exhibits a Nernstian slope, within a linear range of response from 1 to 50 mM CRE concentration. As expected, the response time (15–60 min) primarily depends on the CRE diffusion across the AEM. CRE analysis in urine samples displayed excellent results, without requiring sample pretreatment (before the introduction of the sample in the microfluidic chip) and with high compatibility with development into a potential point-of-care clinical tool. In an attempt to decrease the analysis time, the presented analytical methodology for CRE detection is translated into an all-solid-state platform, in which the enzyme is immobilized on the surface of the ammonium-selective electrode and with the AEM on top. While more work is necessary in this direction, the CRE sensor appears to be promising for CRE analysis in both urine and blood.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 7.4
DOI: 10.1021/ACS.ANALCHEM.9B05231
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“Three-dimensional trace element analysis by confocal X-ray microfluorescence imaging”. Vincze L, Vekemans B, Brenker FE, Falkenberg G, Rickers K, Somogyi A, Kersten M, Adams F, Analytical chemistry 76, 6786 (2004). http://doi.org/10.1021/AC049274L
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC049274L
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“Trace metal analysis of water containing humic substances by X-ray fluorescence”. Vanderborght BM, Van Grieken RE, International journal of environmental analytical chemistry 5, 221 (1978). http://doi.org/10.1080/03067317808071147
Abstract: Chelation by oxine followed by adsorption on activated carbon results in the efficient collection of many trace metal ions, independent of the trace metal concentration and of high alkali and alkaline earth ion abundances. Preconcentration factors around 10000 are often achieved. When this preconcentration procedure is combined with energy-dispersive X-ray fluorescence, accurate and precise analysis can be carried out, as was proven in several experiments. The technique can also be applied for the determination of divalent ions in natural waters containing up to 10 ppm of humic substances. Trivalent ions can quantitatively be collected from natural water provided suKicient activated carbon is added. Omitting the oxine chelation prior to the activated carbon adsorption step still results in collection of a sometimes important fraction of the trace metal ions from natural waters. This is related to organically bound or colloidal forms of the trace metals.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1080/03067317808071147
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“Ultra-thin window electron probe microanalysis of suspended particles in tributaries of Lake Baikal, Siberia”. Semenov MY, Spolnik Z, Granina L, Van Grieken R, International journal of environmental analytical chemistry 85, 377 (2005). http://doi.org/10.1080/03067310500053944
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1080/03067310500053944
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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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“The use of a secondary cathode to analyse solid non-conducting samples with direct current glow discharge mass spectrometry: potential and restrictions”. Schelles W, de Gendt S, Maes K, Van Grieken R, Fresenius' journal of analytical chemistry 355, 858 (1996). http://doi.org/10.1007/S0021663550858
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1007/S0021663550858
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“Voltammetric sensing using an array of modified SPCE coupled with machine learning strategies for the improved identification of opioids in presence of cutting agents”. Ortiz-Aguayo D, De Wael K, del Valle M, Journal Of Electroanalytical Chemistry 902, 115770 (2021). http://doi.org/10.1016/J.JELECHEM.2021.115770
Abstract: This work reports the use of modified screen-printed carbon electrodes (SPCEs) for the identification of three drugs of abuse and two habitual cutting agents, caffeine and paracetamol, combining voltammetric sensing and chemometrics. In order to achieve this goal, codeine, heroin and morphine were subjected to Square Wave Voltammetry (SWV) at pH 7, in order to elucidate their electrochemical fingerprints. The optimized SPCEs electrode array, which have a differentiated response for the three oxidizable compounds, was derived from Carbon, Prussian blue, Cobalt (II) phthalocyanine, Copper (II) oxide, Polypyrrole and Palladium nanoparticles ink-modified carbon electrodes. Finally, Principal Component Analysis (PCA) coupled with Silhouette parameter assessment was used to select the most suitable combination of sensors for identification of drugs of abuse in presence of cutting agents.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Impact Factor: 3.012
DOI: 10.1016/J.JELECHEM.2021.115770
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“Water analysis by spark-source mass-spectrometry after preconcentration on activated carbon”. Vanderborght BM, Van Grieken RE, Talanta : the international journal of pure and applied analytical chemistry 27, 417 (1980). http://doi.org/10.1016/0039-9140(80)80225-6
Abstract: For trace analyses of environmental waters, spark-source mass-spectrometry has been combined with a preconcentration procedure involving chelation of the dissolved trace elements with oxine and subsequent adsorption of the oxinates and naturally occurring organic and colloidal metal species onto activated carbon. The activated carbon is filtered off and ashed at low temperature. The residue is dissolved, an internal standard and pure graphite are added and, after drying, the electrodes are prepared. The photographically recorded mass spectrum is evaluated by a suitable computer routine. The error of the procedure is around 30%. While this preconcentration and analysis procedure is capable of measuring about 40 elements quantitatively, in practice 1025 trace elements are determined simultaneously above the 0.1-μg/l. detection limit, as is illustrated by analyses of drinking water, surface and ground water samples. Although a sophisticated technique, SSMS can be considered for regular panoramic survey analyses.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1016/0039-9140(80)80225-6
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“X-ray spectrometry”. Szalóki I, Osán J, Van Grieken RE, Analytical chemistry 78, 4069 (2006). http://doi.org/10.1021/AC060688J
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC060688J
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“X-ray spectrometry”. Szalóki I, Osán J, Van Grieken RE, Analytical chemistry 76, 3445 (2004). http://doi.org/10.1021/AC0400820
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC0400820
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“X-ray spectrometry”. Szalóki I, Török SB, Injuk J, Van Grieken RE, Analytical chemistry 74, 2895 (2002). http://doi.org/10.1021/AC020241K
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC020241K
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“X-ray spectrometry”. Szalóki I, Török SB, Ro C-U, Injuk J, Van Grieken RE, Analytical chemistry 72, 211 (2000). http://doi.org/10.1021/A1000018H
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/A1000018H
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“X-ray spectrometry”. Török S, Labar J, Schmeling M, Van Grieken R, Analytical chemistry 70, 495r (1998)
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“X-ray spectrometry”. Török SB, Labar J, Injuk J, Van Grieken RE, Analytical chemistry R68, 467 (1996)
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“X-ray spectrometry”. Török SB, Van Grieken RE, Analytical chemistry 64r, 180 (1992)
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“X-ray spectrometry”. Markowicz AA, Van Grieken RE, Analytical chemistry 62, 101r (1990). http://doi.org/10.1021/AC00211A001
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1021/AC00211A001
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