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EXTRACTION AND IDENTIFICATION OF ARSENOSUGARS IN COMMERCIALLY AVAILABLE SEAWEEDS
Wei, X., J A. Shoemaker, P A. Gallagher, C A. Schwegel, AND J T. Creed. EXTRACTION AND IDENTIFICATION OF ARSENOSUGARS IN COMMERCIALLY AVAILABLE SEAWEEDS. Presented at International Ion Chromatography Symposium, San Jose, CA, September 12-15, 1999.
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.
Arsenosugars, mostly in the form of dimethylarsinylribosides, are widely found in marine plants. Since the first arsneosugar was identified in 1982, fifteen arsenosugars have been isolated and identified as algal constituents. Seaweed has been a popular dietary food in Asian Pacific culture for ages, however, the metabolic fate of arsenosugars remains virtually an unknown. Preliminary toxicological studies showed that arsenosugars are much less toxic than inorganic arsenics while arsenic speciation studies on human urine after algea ingestion suggested that arsenosugars experienced certain metabolic changes and produce DMA as well as a few other unknown arsenic metabolites. From an exposure assessment perspective the arsenosugars and the associated metabolites are potential false positives in a urinary arsenic exposure assessment. The first step in evaluating the impact of arsenosugars on a urinary arsenic exposure assessment method is to produce a semi-purified standard material and characterize it chromatographically and structurally.
In this study, three arsenosugars, identified via ion chrmatography and hydride generation ICP-MS, were extracted from two commercial seaweeds using Accelerated Solvent Extraction. The extracts were then treated with C18 and fraction collected using a preparatory PRPX-100 column. These crude extracts (containing individual arsenosugars) were then characterized chromatographically using IC-ICP-MS and structurally using IC-electrospray MS/MS.