IDENTIFICATION OF METHYLATED METABOLITES OF INORGANIC ARSENIC BY THIN-LAYER CHROMATOGRAPHY

TLC on cellulose plates was used to identify methylated products of in organic arsenic metabolism (monomethylarsonate and dimethylarsinate) i n biological samples. Two solvent systems were tested: methanol-ammoni um hydroxide (8:2) and isopropanol-acetic acid-water (10:1:2.5). The l atter solvent system produced the most satisfactory separation of radi olabelled methylated arsenic compounds in aqueous solution, in rat liv er cytosol incubated with carrier-free or 1 mu M [As-73]arsenite and i n urine of mice given carrier-free [As-73]arsenate or 5 mg of [As-73]a rsenate/kg per os. Oxidation of samples by hydrogen peroxide improved the separation and quantitation of monomethylarsonate in both biologic al matrices.