Analysis of soil samples from the San Joaquin Valley of California (original) (raw)
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Environmental Science & Technology, 1997
Understanding the speciation of the multioxidation states of selenium is vital to predicting the mineralization, mobilization, and toxicity of the trace element in natural systems. A sequential extraction scheme (SES) was developed for identification of Se oxidation states that first employed 0.1 M (pH 7.0) K 2 HPO 4 -KH 2 PO 4 (P-buffer) to release soluble selenate (Se +VI ) and selenide (Se -II ) and ligandexchangeable selenite (Se +IV ). The second step involved oxidation of organic materials with 0.1 M K 2 S 2 O 8 (90°C) to release Se -II and Se +IV associated or occluded with organic matter. The final step used HNO 3 (90°C) to solubilize insoluble Se remaining in the sample. The solubilized Se compounds were speciated by a selective hydride generation atomic absorption spectrophotometry technique. Accuracy of the developed SES method (96-103% recovery) was verified by use of prepared Se compounds of known speciation, NIST standard reference materials, and existing seleniferous soils. The average precision (relative standard deviation) for the P-buffer extraction ranged from 5.5 to 7.7% (n ) 12); the precision of the persulfate extraction ranged from 2.6 to 8.4% (n ) 12); and the precision of the nitric acid extraction ranged from 2.8 to 7.4% (n ) 12) for three soils extracted at four different time periods. The method was applied to analyze Se species in seleniferous plant, soil, and sediment samples.
Atomic spectrometry update. Environmental analysis
Journal of Analytical Atomic Spectrometry, 2002
This is the twenty-forth annual review published in JAAS of the application of atomic spectrometry to the chemical analysis of environmental samples. This Update refers to papers published approximately between September 2007 and August 2008. In the analysis of air, work is focused on the need to collect and characterise ultrafines, i.e. particles below 100 nm in size, and such research is being facilitated through the development of air sampler technologies for subsequent off-line analysis of particles and aerosol mass spectrometric techniques for real-time measurements. In the analysis of water elemental speciation and development of vapour generation techniques for metalloid species continue to attach attention. Data quality and metrological issues are receiving renewed interest in part due to an increase in water quality regulations. In the field of soil and plant analysis, elemental fraction and speciation protocols based upon sequential extraction procedures, chromatographic separation procedures and synchrotron radiation x-ray techniques continue to be utilized and developed. As noted in previous Updates, laser ablation continues to go from strength to strength in being adopted as a solid sampling tool in geochemical analysis. Work continues to be focused on the production, characterization and certification of new geological reference materials. Feedback on this review
MGAU: A new analysis code for measuring {sup 235}U enrichments in arbitrary samples
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information), 1994
This is a preprint of a paper intended for publication in a journal or proceedings. Since changesmaybe made before publication,this preprintis made availablewith the understandingthat it will not be cited or reproducedwithout the permission of the author.. DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED DISCLAIMER This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes.
Quantitative Analyses of Trace Elements in Environmental Samples: Options and (Im)possibilities
The main aim of contemporary ecotoxicological studies is to determine the bioavailability, toxicity and risk relationships of trace-element contaminants in ecosystems. Discussions thus focus primarily on the concentrations of elements in soils, their dynamics, and the impact they have on microorganisms, plants, animals and the ecosystem as a whole. However, before the basic ecotoxicological principles can be discussed, the appropriate analytical methods for addressing particular question(s) need to be chosen from among the broad array of physicochemical analytical methods that are available. Together with the sampling strategy and preparation, these are key issues that affect the final outcome. In this chapter, we mainly focus on the presentation and use of X-ray fluorescence/absorption-based techniques. These include standard and total reflection X-ray fluorescence, micro-proton-induced X-ray emission, and X-ray absorption spectroscopy (such as extended X-ray absorption fine structure and X-ray absorption near-edge structure) for the analysis of trace-element concentrations and their coordination in biological samples.
Atomic spectrometry update – a review of advances in environmental analysis
Journal of Analytical Atomic Spectrometry, 2021
Introduction 2 Air analysis 2.1 Sampling techniques 2.2 Reference materials and calibrants 2.3 Sample preparation 2.4 Instrumental analysis 2.4.1 Atomic absorption and emission spectrometries 2.4.2 Mass spectrometry 2.4.2.1 Inductively coupled plasma mass spectrometry 2.4.2.2 Other mass spectrometry techniques 2.4.3 X-ray spectrometry 2.4.4 Combustion-based techniques 2.4.5 Other instrumental techniques 3 Water analysis 3.1 Certification of reference materials and metrological investigations Page 12 of 125 235 U 1 H + isobaric interference on 236 U. By cleverly exploiting the fact that the hydride form of UO + (UOH +) is less prone to formation in the plasma than UH + , together with the use of a desolvating nebuliser, it was possible to constrain the 235 U 16 O 1 H + / 235 U 16 O + formation rate to ca. 10-7 so 236 U/ 238 U ratios of <10-8 could be determined successfully for material deposited from the Fukushima Daiichi nuclear incident. Siloxanes in gaseous fuels, even at low concentrations, can be problematic because, upon combustion, amorphous Si can deposit and cause damage within combustion systems or fuel cells. The LOQ for Si of ca. 0.01 mg m-3 for a new GC-ICP-MS approach to the analysis of fuels was 37 below the benchmark limit of ≤0.1 mg m-3 designed to protect machinery. The Hg 0 concentration output from the NIST prime calibrator (see section 2.1) was certified 38 using ID-CV-ICP-MS at selected span points over the range 0.25 to 38 µg m-3. Two procedures were used, a direct gas analysis approach and a preconcentration method that involved trapping defined gas volumes on activated carbon. The direct measurement approach yielded expanded MU ranging from 5.5% at 0.5 µg m-3 to 1% at 38 µg m-3 with a LOQ of 0.06 µg m-3 , whereas sample preconcentration yielded an expanded MU of 1% across this range with a LOQ of 0.001 µg m-3. The single particle ICP-MS analysis of atmospheric particles deposited in ice-core samples was performed 39 for the first time using CFA coupled to ICP-TOF-MS. The fact that Al and Mg signals were associated with Fe signals emanating from Fe-rich particles suggested that clay minerals such as illite were the dominant components in the particles being examined. Use of a dry aerosol provided 40 a significant gain in ion extraction from a plasma thereby making it possible to now size silver and titanium NPs at 3.5 and 12.1 nm, an improvement of 29 and 37% over that achievable under wet plasma conditions.
2013 Atomic spectrometry update—A review of advances in environmental analysis
Journal of Analytical Atomic Spectrometry, 2014
This is the 30th annual review of the application of atomic spectrometry to the chemical analysis of environmental samples. This Update refers to papers published approximately between August 2013 and July 2014 and continues the series of Atomic Spectrometry Updates (ASUs) in environmental analysis 1 that should be read in conjunction with other related ASUs in the series, namely: clinical and biological materials, foods and beverages, 2 advances in atomic spectrometry and related techniques, 3 elemental speciation, 4 X-ray fluorescence spectrometry, 5 and the analysis of metals, chemicals and functional materials. 6 In the field of air analysis, highlights within this review period included: the use of 3D printing technology for the rapid prototyping of new air sampler components; single particle ICP-MS studies; use of a new triple-quadrupole ICP-MS for the analysis of radioactive species and the use of FEG-SEM and IBA for the analysis of gunshot residues. In the field of water analysis, methods continue to be developed: for the extraction and preconcentration of elements; speciation of As, Cr, Hg and Sb forms and determination of
Talanta, 2001
Mineralization procedures for arsenic and selenium analysis are usually limited to wet digestion methods owing to high volatility of these analytes. On the other hand, variable amounts of silicon in some types of samples imply elaborated mineralization procedures to liberate analytes which may be retained in an insoluble residue. Consequently, methods for such material generally include an hydrofluoric step followed by an evaporation to dryness. This type of mineralization is most easily accomplished using a dry ashing procedure. For plant analysis, a well validated and readily applicable dry ashing method is used for a long time in several laboratories but up today one could suppose that As and Se determinations cannot be performed after such a type of mineralization. Surprisingly, it has been observed that for plant samples these analytes are detected even after a calcination at 450°C. The general usefulness of a dry ashing method for analysis of all other analytes (main, minor and trace elements) incitates us to also verify As and Se recoveries. Results obtained in this work indicate clearly that plants of terrestrial origin may be mineralized using dry ashing procedure without As and Se losses. This statement was confirmed by analyses of several reference terrestrial plant samples (RMs) and laboratory control samples. Another confirmation was given by the direct graphite furnace analysis of the same plant samples but in slurried form (SS-ETAAS). As a direct consequence, As and Se analysis in terrestrial plants no more necessitates a separate preparation methodology. On the other hand, significant losses of As and Se were observed for aquatic plants, e.g. algaes. For the analysis of this type of samples, a separate wet digestion procedure remains unavoidable if the determination of As and Se has to be considered. Also some preparation procedures were tested for As and Se-analysis of soil and sediment reference samples. In these cases the wet digestion with a mixture of nitric, perchloric and hydrofluoric acids seems to remain the best alternative. : S 0 0 3 9 -9 1 4 0 ( 0 0 ) 0 0 6 5 2 -4 E. Vassile6a et al. / Talanta 54 (2001) 187-196 188