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627453 
Journal Article 
Speciation of dimethylarsinous acid and trimethylarsine oxide in urine from rats fed with dimethylarsinic acid and dimercaptopropane sulfonate 
Lu, X; Arnold, LL; Cohen, SM; Cullen, WR; Le, XC 
2003 
Yes 
Analytical Chemistry
ISSN: 0003-2700
EISSN: 1520-6882 
75 
23 
6463-6468 
English 
14640715 
WOS:000186986000017 
Speciation of arsenic in urine from rats treated with dimethylarsinic acid (DMA(V)) alone or in combination with dimercaptopropane sulfonate (DMPS) were studied. Methods were developed for the determination of the methylarsenic metabolites, especially trace levels of dimethylarsinous acid (DMA(III)) and trimethylarsine oxide (TMAO), in the presence of a large excess of DMA(V). Success was achieved by using improved ion-exchange chromatographic separation combined with hydride generation atomic fluorescence detection. Micromolar concentrations of DMA(III) were detected in urine of rats fed with a diet supplemented with either 100 microg/g of DMA(V) or a mixture of 100 microg/g of DMA(V) and 5600 microg/g of DMPS. No significant difference in the DMA(III) concentration was observed between the two groups; however, there was a significant difference in TMAO concentrations. Urine from rats fed with the diet supplemented with DMA(V) alone contained 73 +/- 30 microM TMAO, whereas urine from rats fed with the diet supplemented with both DMA(V) and DMPS contained only 2.8 +/- 1.4 microM TMAO. Solutions containing mixtures of 100 microg/L DMA(V) or TMAO and 5600 microg/L DMPS did not show reduction of DMA(V) and TMAO. The significant decrease (p < 0.001) of the TMAO concentration in rats administered with both DMA(V) and DMPS suggests that DMPS inhibits the biomethylation of arsenic.