Dimethylthioarsenicals as arsenic metabolites and their chemical preparations.

Two unidentified arsenic metabolites were detected in the liver of rats on a gel filtration column by HPLC inductively coupled argon plasma mass spectrometry after an injection of dimethylarsinic (DMAV), dimethylarsinous (DMAIII), monomethylarsonic (MMAV), or monomethylarsonous (MMAIII) acid. The same arsenicals were also produced in vitro by incubation of DMAIII in the liver supernatant but not by DMAV. The two arsenic metabolites eluted at the same retention times as those of the two arsenicals prepared by reaction of DMAV with either thiosulfate plus disulfite or hydrogen sulfide or sodium sulfide plus sulfuric acid. The faster and slower eluting products on a gel filtration column were assigned as dimethyldithioarsinic acid (dimethylarsinodithioic acid) (DMTAV) and dimethylthioarsinous acid (DMTAIII) from mass spectrometric data at m/z = 170 and 138 by electrospray ionization mass spectrometry with negative and positive ion modes, respectively. They were prepared selectively by reacting DMAV with hydr...