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EXTRACTION AND DETECTION OF ARSENICALS IN SEAWEED VIA ACCELERATED SOLVENT EXTRACTION WITH ION CHROMATOGRAPHIC SEPARATION AND ICP-MS DETECTION
Citation:
Gallagher, P A., J A. Shoemaker, X. Wei, C A. Schwegel, AND J T. Creed. EXTRACTION AND DETECTION OF ARSENICALS IN SEAWEED VIA ACCELERATED SOLVENT EXTRACTION WITH ION CHROMATOGRAPHIC SEPARATION AND ICP-MS DETECTION. FRESENIUS'JOURNAL OF ANALYTICAL CHEMISTRY 369(1):71-80, (2001).
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:
An accelerated solvent extraction (ASE) device was evaluated as a semi-automated means of extracting arsenicals from ribbon kelp. Objective was to investigate effect of experimentally controllable ASE parameters (pressure, temperature, static time and solvent composition) on extraction efficiencies of arsenicals from seaweed. Changes in pressure (500-3000psi) and static time (1min-5min) parameters resulted in increase in extraction efficiency (after 3 ASEcycles) of <3% and 1% respectively. A solvent (50/50 MeOH/H2O) temperature increase from ambient to 60oC produced increase in extraction efficiency of 19% after first ASE extrac- tion. This difference was reduced to 9% after 3 ASE cycles. An extraction temperature of 120oC using 50/50 MeOH/H2O mixture produced improved extraction efficiencies (~11% after 3 ASE cycles) but increase in co-extractants was evident by dark ring in C18 sample preparation cartridge. Solvent compositions containing 50/50-0/100 MeOH/H2O produced extraction efficiencies within 5% after 3 ASE cycles. Finally particle size was evaluated by comparing a standard homogenized sample with a cryogenically ground sample. The cryogenically ground sample produced higher (72.4% cryogenic; 59.0% conventional mill) extraction efficiencies after first ASE cycle but difference decreased to less than 2% after 3 ASE cycles. In general extraction efficiencies for ribbon kelp (approximately 75%) using ASE was fairly independent (+/-3%) of pressure, static time and particle size after 3 ASE cycles.