Arsenic analysis

A major advantage of this hydride approach lies in the separation of the remaining elements of the analyte solution from the element to be determined. Because the volatile hydrides are swept out of the analyte solution, the latter can be simply diverted to waste and not sent through the plasma flame Itself. Consequently potential interference from. sample-preparation constituents and by-products is reduced to very low levels. For example, a major interference for arsenic analysis arises from ions ArCE having m/z 75,77, which have the same integral m/z value as that of As+ ions themselves. Thus, any chlorides in the analyte solution (for example, from sea water) could produce serious interference in the accurate analysis of arsenic. The option of diverting the used analyte solution away from the plasma flame facilitates accurate, sensitive analysis of isotope concentrations. Inlet systems for generation of volatile hydrides can operate continuously or batchwise. 

Arsenical copper alloys, 3 271-272, 272 Arsenical herbicides, 13 325 Arsenical insecticides, 14 339 Arsenic alloys, 3 271-272 Arsenical pesticides, 13 298 Arsenic analysis, of water, 26 40-41 Arsenic carbide (2 6), 4 649t Arsenic-catalyzed liquid-phase process, 10 655... 

Oakberg, K., Levy, T., and Smith, P. (2000). A method for skeletal arsenic analysis, applied to the chalcolithic copper smelting site of Shiqmim, Israel. Journal of Archaeological Science 27 859-901. 

Tahir M.A., Rasheed H. and Malana A. Method development for arsenic analysis by modification in spectrpho to metric technique, Drik. Water Eng.Sci. Discuss. 1, 135-154 (2008). 

Figure 2.2-1 illustrates how arsenic wastewater flows through that facility. The first three arsenic sources were thought to be minor and composed of soluble araenic. These waste streams flow directly to the HF preholding tank and are not involved in the Slurry Recovery process. Sample acquisition for these sources required the operator to perform the wash process in a container with graduations on the sides for volume measurement. Samples were taken after the processes were completed. Arsenic analysis waa done on the measured wash solution and with this analysis and the number of ingots or wafers cleaned or etched, a total arsenic contribution was calculated. 

Arsenic analysis of Che other waste streams at HP s facility completed the chemical characterization. Results are listed in Table 2.2-1 and illustrated in Figures 2.2-2, 2.2-3 and 2.2-4. Figure 2.2-2 indicates the sources and amounts of the average monthly arsenic weights chat are produced at HP s San Jose facility (Table 2.2-1 data column 2). The most important point here is that nearly all (about 94%) of the arsenic that flows to the HF Treatment System is from the Slurry Recovery process and is essentially all solid GaAs particles. The remainder is entirely soluble arsenic from the cleaning and etching processes. 

Dry tissue (1—3 g) is digested with 30 ml of nitric acid, sulphuric and perchloric acids (4 4 1). After heating for approximately 1.5h, the cooled solution is transferred to a 100 ml flask, 30 ml hydrochloric acid added and diluted to 100 ml with water. Suitable aliquots, up to 20 ml, of this solution are used for the subsequent arsenic analysis. 

A case of suicide due to the ingestion of a wood preservative solution was investigated by Cross et al. [20]. The subject swallowed an unknown quantity of a corrosive solution containing copper sulphate, sodium dichromate and an arsenic compound. Death occurred 36 h after ingestion and the cause of death was reported as poisoning by a corrosive substance. The results of the arsenic analysis are given in Table 4. 

Arsenic analysis by atomic absorption selenium analysis by fluorimetry molybdenum analysis by colorimetry. 

Laboratory methods. Methods for arsenic analysis in water, food, and biological samples... 

Early colorimetric methods for arsenic analysis used the reaction of arsine gas with either mercuric bromide captured on filter paper to produce a yellow-brown stain (Gutzeit method) or with silver diethyl dithiocarbamate (SDDC) to produce a red dye. The SDDC method is still widely used in developing countries. The molybdate blue spectrophotometric method that is widely used for phosphate determination can be used for As(V), but the correction for P interference is difficult. Methods based on atomic absorption spectrometry (AAS) linked to hydride generation (HG) or a graphite furnace (GF) have become widely used. Other sensitive and specihc arsenic detectors (e.g., AFS, ICP-MS, and ICP-AES) are becoming increasingly available. HG-AES, in particular, is now widely used for routine arsenic determinations because of its sensitivity, reliability, and relatively low capital cost. 

Arsenic recoveries of 89.4 to 104.4% were experienced from an activated sludge effluent sample. Employing the high-sensitivity arsenic analysis by atomic absorption resulted in arsenic recoveries of 99.2-100.8%. 

The effects of ultra-violet irradiation as a function of time for triphenylarsine oxide, DSMA and DMAA are illustrated in Figured. The extent of arsenic recovery using photooxidation in conjunction with high-sensitivity arsenic analysis when applied to the AF and SBE samples is shown in Table 10. 

There were several observations made concerning the arsenic analysis by both the AgDDC technique and the high-sensitivity atomic absorption procedure during the course of this investigation. Turbidity problems were initially encountered in the AgDDC colorimetric procedure. 

Water sample collection procedures used in this study are outlined by Koterba et al. (1995). Field measurements included temperature, dissolved oxygen, pH, specific conductance, redox potential, alkalinity, and field tests for total and ferrous iron, nitrate, ammonia, sulfate, sulfide, turbidity, and phosphate (Haack and Trecanni, 2000). Samples collected for trace-element analysis were filtered to pass 0.45 pm. Samples for arsenic analysis included sub-samples for total and filtered arsenic, arsenate, and arsenite (Kim, 1999). 

Generation of Volatile Hydrides (11). The use of commercial sodium borohydride as a reducing agent for the generation of volatile arsine (AsH3) in trace arsenic analysis is often complicated by trace (ppb) arsenic impurities in the borohydride. The following procedure using polymer-bound borohydride has eliminated these problems ... 

An analytical procedure consists of proper sampling, sample storage, if necessary, sample preparation, which is different for total elemental analysis and species analysis, separation procedures, if speciation or preconcentration is required, the quantification step, and quality assurance. All this applies to arsenic analysis and thus will be treated subsequently and demonstrated by practical examples for all these steps. Since speciation for arsenic is of paramount importance, it will be described in some detail. 

Edwards M., Patel S., McNeill L., Chen H.-W., Frey M., Eaton A.D., /Vntweiler R.C., Taylor H.E. Considerations in arsenic analysis and speciation. Journal of the /American Water Works Association 1998 90(3) 103-113. 

An interesting example of the application of the isotherm model comes from a case study of two coagulation utilities that utilize the same river as their water source, with the plant intakes only a few miles apart. One utility practices alum coagulation while the other uses ferric chloride. These utilities participated in a year-long project where once a week they reported raw water quality (pH and temperature) and treatment conditions (coagulant dose and pH) and collected influent and treated water samples for arsenic analysis. 

Arsenic analysis at polymer electrodes has also been the subject of investigation. Upt e into a polypyrrole film can be used for preconcentration of arsenic species and subsequent analysis by HPLC/ICP/MS 63). 

The analytical sensitivity for arsenic has been improved from 0.60 pg mL to 0.10 pg mL by the use of an argon-hydrogen flcime (instead of air-acetylene) and a 10 cm propane burner (instead of a 10 cm acetylene burner) analysed at a wavelength of 197.2 nm, and this flame is recommended in arsenic analysis. The argon-hydrogen combination is highly explosive and should only be used by trained personnel. 

The determination of arsenic in urine samples to determine exposure requires the hyphenation of hydride generation with ICP-MS. This is because total arsenic analysis, which has been vastly improved with the introduction of CCT and the removal of the ArCl interference, still includes some arsenic species that are present in urine as a result of seafood contributions. The reduction of As +, DMA and MMA (dimethylarsinic acid and monomethylarsonic acid) to As " " with L-cysteine and hydrochloric acid and subsequent hydride generation by mixing with sodium borohydride will measure all the arsenic species except arsenobetaine and arsenocholine. The hydride gas line can be simply connected to the spray chamber (replacing the nebuliser gas) and arsenic is measured using a dry plasma. The hydride generator system removes both the chloride interference (because only the AsHs gas enters the plasma) and the dietary component of exposure (because AB and AC are not reduced to As +). 

Song Y, Swain GM (2007) Development of a method for total inorganic arsenic analysis using anodic stripping voltammetry and a Au-coated, diamond thin-film electrodes. Anal Chem 79 2412-2420... 

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