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INVESTIGATION OF THE STABILITY OF AN ARSENOSUGAR IN MOUSE CECUM SAMPLES USING IC-ICP-MS AND LC-ESI-MS/MS DETECTION
Citation:
CONKLIN, S. D., M. W. FRICKE, A. ACKERMAN, P. A. CREED, JOHN T. CREED, M. J. KOHAN, K. HERBIN-DAVIS, AND D. J. THOMAS. INVESTIGATION OF THE STABILITY OF AN ARSENOSUGAR IN MOUSE CECUM SAMPLES USING IC-ICP-MS AND LC-ESI-MS/MS DETECTION. Presented at 2005 Winter Conference on Plasma Spectrochemistry, Budapest, INDIA, January 30 - February 03, 2005.
Impact/Purpose:
The goal is to develop an extraction protocol that mimics the human digestive tract and then to use it to assess the bioavailable fraction of arsenic from complex dietary mixtures such as a daily composite -- to move current methods toward a better human physiologically-based exposure estimate method which approximates the "true" bioavailability of arsenic within an environmental or dietary matrix.
Description:
Arsenosugar exposures occur mainly through seafood and seaweed ingestion, and the major metabolite present in urine is DMA. Understanding the pathway of this conversion is the goal of this ongoing study. Preliminary studies indicated that very little of the arsenosugar degraded to DMA in a synthetic stomach or in pH adjusted control samples. The data presented will examine the stability of an arsenosugar, As(392), in anaerobic cultures of the microflora isolated from the ceca of laboratory mice. These data are relevant in assessing the role of the gastrointestinal microflora in degradation of ingested arsenosugars.
Specifically, data will be presented which indicate that the arsenosugar is converted primarily to its sulfur analog in the small intestine. This conversion appears to take place quickly at 370C. IC-ICP-MS data indicate a good mass balance between the spiked arsenosugar and the resulting by-products. In addition, LC-ESI-MS/MS spectra of the sulfur containing arsenosugar in the cecal samples compare well with those of a synthetic standard. Details regarding the chromatographic conditions used in the characterization of the standard will also be reported.