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Frank Vanhaecke - One of the best experts on this subject based on the ideXlab platform.
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multi element la icp ms analysis of the clay fraction of archaeological pottery in provenance studies a methodological investigation
Journal of Analytical Atomic Spectrometry, 2020Co-Authors: Marieke Vannoorenberghe, Thibaut Van Acker, Joke Belza, Dimitri Teetaert, Philippe Crombe, Frank VanhaeckeAbstract:Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is an increasingly popular direct solid sampling micro-analytical technique for multi-element analysis in provenance studies of archaeological pottery. However, the development and use of a reliable quantification strategy for the analysis of pottery clay via ns-LA-ICP-MS is not self-evident due to the lack of commercially available matrix-matched clay reference materials covering a wide range of characterized element concentrations. In this work, the capabilities and limitations of various Calibration approaches were evaluated, based on the analysis of NIST SRM 679 Brick Clay as a model sample. Calibration relied on the use of either (i) 5 glass reference materials or (ii) the matrix-matched reference material New Ohio Red Clay (NORC) as External Calibration standard(s). Four Calibration strategies were compared and it was shown that (a) External Calibration without internal standard correction is not suitable when using glass reference materials for Calibration, but can be used in the case of Calibration against a clay reference material, (b) different sum normalization approaches produce results that are very similar to each other and (c) glass reference materials used as standards in an External Calibration approach with internal standard correction or a sum normalization method can provide accurate results for a wide range of major, minor and trace elements. Finally, the utility of an appropriate sum normalization Calibration approach was illustrated by analysis of 10 sediments relevant to provenance studies of Final Mesolithic and Early Neolithic pottery in the Scheldt valley and their successful discrimination employing linear discriminant analysis (LDA) based on 44 element concentrations. The use of polished sediment thin sections in combination with transmitted light microscopy enabled the clay fraction of the sediments only to be meticulously sampled. A dedicated outlier rejection protocol was applied to minimize the contribution of non-visible constituents.
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a comparison of laser ablation inductively coupled plasma mass spectrometry and high resolution continuum source graphite furnace molecular absorption spectrometry for the direct determination of bromine in polymers
Spectrochimica Acta Part B: Atomic Spectroscopy, 2017Co-Authors: Stijn Van Malderen, Jefferson Santos De Gois, Heloisa R Cadorim, Bernhard Welz, Frank VanhaeckeAbstract:Abstract This work describes the development and comparison of two methods for the direct determination of Br in polymer samples via solid sampling, one using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and the other using high-resolution continuum source graphite furnace molecular absorption spectrometry with direct solid sample analysis (HR-CS SS-GF MAS). The methods were optimized and their accuracy was evaluated by comparing the results obtained for 6 polymeric certified reference materials (CRMs) with the corresponding certified values. For Br determination with LA-ICP-MS, the 79Br+ signal could be monitored interference-free. For Br determination via HR-CS SS-GF MAS, the CaBr molecule was monitored at 625.315 nm with integration of the central pixel ± 1. Bromine quantification by LA-ICP-MS was performed via External Calibration against a single CRM while using the 12C+ signal as an internal standard. With HR-CS SS-GF MAS, Br quantification could be accomplished using External Calibration against aqueous standard solutions. Except for one LA-ICP-MS result, the concentrations obtained with both techniques were in agreement with the certified values within the experimental uncertainty as evidenced using a t-test (95% confidence level). The limit of quantification was determined to be 100 μg g− 1 Br for LA-ICP-MS and 10 μg g− 1 Br for HR-CS SS-GF MAS.
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radial line scans as representative sampling strategy in dried droplet laser ablation of liquid samples deposited on pre cut filter paper disks
Spectrochimica Acta Part B: Atomic Spectroscopy, 2014Co-Authors: Frank Vanhaecke, Winfried Nischkauer, Sebastien Bernacchi, Christoph Herwig, Andreas LimbeckAbstract:Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via External Calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts and can range from body fluids, like blood or urine, to fuel additives or fermentation broths. Specialized nebulizer systems or careful digestion and dilution are required to tackle such demanding sample matrices. One alternative approach is to convert the liquid into a dried solid and to use laser ablation for sample introduction. Up to now, this approach required the application of internal standards or matrix-adjusted Calibration due to matrix effects. In this contribution, we show a way to circumvent these matrix effects while using simple External Calibration for quantification. The principle of representative sampling that we propose uses radial line-scans across the dried residue. This compensates for centro-symmetric inhomogeneities typically observed in dried spots. The effectiveness of the proposed sampling strategy is exemplified via the determination of phosphorus in biochemical fermentation media. However, the universal viability of the presented measurement protocol is postulated. Detection limits using laser ablation-ICP-optical emission spectrometry were in the order of 40 μg mL− 1 with a reproducibility of 10 % relative standard deviation (n = 4, concentration = 10 times the quantification limit). The reported sensitivity is fit-for-purpose in the biochemical context described here, but could be improved using ICP-mass spectrometry, if future analytical tasks would require it. Trueness of the proposed method was investigated by cross-validation with conventional liquid measurements, and by analyzing IAEA-153 reference material (Trace Elements in Milk Powder); a good agreement with the certified value for phosphorus was obtained.
Jefferson Santos De Gois - One of the best experts on this subject based on the ideXlab platform.
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a comparison of laser ablation inductively coupled plasma mass spectrometry and high resolution continuum source graphite furnace molecular absorption spectrometry for the direct determination of bromine in polymers
Spectrochimica Acta Part B: Atomic Spectroscopy, 2017Co-Authors: Stijn Van Malderen, Jefferson Santos De Gois, Heloisa R Cadorim, Bernhard Welz, Frank VanhaeckeAbstract:Abstract This work describes the development and comparison of two methods for the direct determination of Br in polymer samples via solid sampling, one using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and the other using high-resolution continuum source graphite furnace molecular absorption spectrometry with direct solid sample analysis (HR-CS SS-GF MAS). The methods were optimized and their accuracy was evaluated by comparing the results obtained for 6 polymeric certified reference materials (CRMs) with the corresponding certified values. For Br determination with LA-ICP-MS, the 79Br+ signal could be monitored interference-free. For Br determination via HR-CS SS-GF MAS, the CaBr molecule was monitored at 625.315 nm with integration of the central pixel ± 1. Bromine quantification by LA-ICP-MS was performed via External Calibration against a single CRM while using the 12C+ signal as an internal standard. With HR-CS SS-GF MAS, Br quantification could be accomplished using External Calibration against aqueous standard solutions. Except for one LA-ICP-MS result, the concentrations obtained with both techniques were in agreement with the certified values within the experimental uncertainty as evidenced using a t-test (95% confidence level). The limit of quantification was determined to be 100 μg g− 1 Br for LA-ICP-MS and 10 μg g− 1 Br for HR-CS SS-GF MAS.
Meredith Lisle - One of the best experts on this subject based on the ideXlab platform.
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use of laser ablation inductively coupled plasma time of flight mass spectrometry to identify the elemental composition of vanilla and determine the geographic origin by discriminant function analysis
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Ellen Hondrogiannis, Erin Ehrlinger, Alyssa Poplaski, Meredith LisleAbstract:A total of 11 elements found in 25 vanilla samples from Uganda, Madagascar, Indonesia, and Papua New Guinea were measured by laser ablation–inductively coupled plasma–time-of-flight–mass spectrometry (LA–ICP–TOF–MS) for the purpose of collecting data that could be used to discriminate among the origins. Pellets were prepared of the samples, and elemental concentrations were obtained on the basis of External Calibration curves created using five National Institute of Standards and Technology (NIST) standards and one Chinese standard with 13C internal standardization. These curves were validated using NIST 1573a (tomato leaves) as a check standard. Discriminant analysis was used to successfully classify the vanilla samples by their origin. Our method illustrates the feasibility of using LA–ICP–TOF–MS with an External Calibration curve for high-throughput screening of spice screening analysis.
Richard E Russo - One of the best experts on this subject based on the ideXlab platform.
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solid matrix transformation and tracer addition using molten ammonium bifluoride salt as a sample preparation method for laser ablation inductively coupled plasma mass spectrometry
Analyst, 2017Co-Authors: Jay W Grate, Jhanis J Gonzalez, Matthew J Ohara, Cynthia M Kellogg, Samuel S Morrison, David W Koppenaal, George C Y Chan, Vassilia Zorba, Richard E RussoAbstract:Solid sampling and analysis methods, such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), are challenged by matrix effects and Calibration difficulties. Matrix-matched standards for External Calibration are seldom available and it is difficult to distribute spikes evenly into a solid matrix as internal standards. While isotopic ratios of the same element can be measured to high precision, matrix-dependent effects in the sampling and analysis process frustrate accurate quantification and elemental ratio determinations. Here we introduce a potentially general solid matrix transformation approach entailing chemical reactions in molten ammonium bifluoride (ABF) salt that enables the introduction of spikes as tracers or internal standards. Proof of principle experiments show that the decomposition of uranium ore in sealed PFA fluoropolymer vials at 230 °C yields, after cooling, new solids suitable for direct solid sampling by LA. When spikes are included in the molten salt reaction, subsequent LA-ICP-MS sampling at several spots indicate that the spikes are evenly distributed, and that U-235 tracer dramatically improves reproducibility in U-238 analysis. Precisions improved from 17% relative standard deviation for U-238 signals to 0.1% for the ratio of sample U-238 to spiked U-235, a factor of over two orders of magnitude. These results introduce the concept of solid matrix transformation (SMT) using ABF, and provide proof of principle for a new method of incorporating internal standards into a solid for LA-ICP-MS. This new approach, SMT-LA-ICP-MS, provides opportunities to improve Calibration and quantification in solids based analysis. Looking forward, tracer addition to transformed solids opens up LA-based methods to analytical methodologies such as standard addition, isotope dilution, preparation of matrix-matched solid standards, External Calibration, and monitoring instrument drift against External Calibration standards.
Owen K Ash - One of the best experts on this subject based on the ideXlab platform.
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minimizing interferences in the quantitative multielement analysis of trace elements in biological fluids by inductively coupled plasma mass spectrometry
Clinical Chemistry, 1997Co-Authors: Chiungsheng Hsiung, J D Andrade, Robert Costa, Owen K AshAbstract:The determination of trace and ultratrace elements in biological fluids, including urine and serum, by inductively coupled plasma mass spectrometry (ICP-MS) is discussed. Nonspectral interferences and their corrections by External Calibration and calibrator addition are discussed in detail. External Calibration with internal Calibration and dilution is mostly sufficient to correct for encountered biological matrix effects. For some elements, such as Cs and Zn, the use of calibrator addition provides more accurate results. The importance of spectral interferences and their elimination by isotope selection was also studied. Two examples, Cu and Zn, demonstrate the prime importance of selecting an isotope with minimal polyatomic interferences for analysis. By using 65Cu and 68Zn, accurate results for urine and serum can be obtained without excessive pretreatment of samples. Two reference materials, Bio-Rad Lyphochek urine and Kaulson Contox sera, were analyzed. Accuracy was evaluated by comparison with target values, and precision was estimated by the CV within 95% confidence.
