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ACCELERATED SOLVENT EXTRACTION OF ARSENICALS FROM ENVIRONMENTAL MATRICES WITH ION CHROMATOGRAPHY SEPARATION AND ICP-MS DETECTION
Citation:
Gallagher, P A., C A. SchwegelBrockhoff, S Murray, J T. Creed, X. Wei, J. W. McKiernan, AND J. A. Caruso. ACCELERATED SOLVENT EXTRACTION OF ARSENICALS FROM ENVIRONMENTAL MATRICES WITH ION CHROMATOGRAPHY SEPARATION AND ICP-MS DETECTION. Presented at 2000 Winter Conference on Plasma Spectrochemistry, Ft. Lauderdale, FL, January 10-15, 2000.
Impact/Purpose:
To develop an arsenic speciation protocol for the analysis of dietary seafoods to be used to support fish advisories, improve relative source (water versus diet) contribution for arsenic and provide improved dietary exposure estimates in future epidemiology (EPI) studies.
Description:
The two major sources of arsenic exposure used in an arsenic risk assessment are water and diet. The extraction, separation and quantification of individual arsenic species from dietary sources is considered an area of uncertainty within the arsenic risk assessment. The uncertainty stems from the lack of species specific information on arsenic from a number of food groups. Arsenic's species dependent toxicity has generated the need for speciation based methodologies. A considerable amount of research in arsenic speciation has been focused on the separation and detection of arsenicals. Recently, the structural information has become increasingly necessary as the list of potential arsenicals continues to grow and chromatographic separation capabilities have somewhat plateaued. An additional area which seems to be lagging behind is the quantitative extraction of arsenicals from dietary samples and composite diet samples. The quantitative extraction is essential in assuring that the extraction procedure is removing all of the toxic species and not selectively removing only the non-toxic arsenicals. Using an extraction procedure which is nearly quantitative allows for a more definitive risk assessment.
Seafood has been assessed to be one of the highest dietary sources of total arsenic. This aspect makes the investigation and identification of arsenicals in seafood and seaweed an exposure source issue for arsenic. One extraction technique which has been applied to the extraction of arsenicals from seafoods is Accelerated Solvent Extraction (ASE). ASE has recently been utilized as a semi-automated technique that allows for optimization via solvent temperature and pressure as well as solvent composition and static time. The development of an analytical procedure surrounding ASE requires the need for certain quality control (QC) samples to be analyzed. The Laboratory Fortified Blank (LFB) is one of these QC samples. The analysis of a LFB by the ASE requires placing a spike of the analytes in a blank ASE cell containing the appropriate support matrix. Poor percent recoveries of LFBs have led to a detailed investigation of the mechanics of the ASE extraction. This presentation will focus on a complete verification of this technique presented in terms of recoveries of LFBs and Laboratory Fortified Matrices (LFMs). This will include an evaluation of the frits, filters, dispersion media, extraction solvents and the appropriate blowdown technique.