Identification of hydrogen selenide and other volatile selenols by derivatization with 1-fluoro-2,4-dinitrobenzene

A procedure is described for the trapping and identification of hydrogen selenide and methyl selenol (CH3SeH). The volatile selenols were generated by reducing selenious acid or dimethyldiselenide with Zn dust and hydrochloric acid under a stream of nitrogen and passing into a trapping solution compoosed of 50 mm 1-fluoro-2,4-dinitrobenzene plus 83 mm sodium bicarbonate in 67% dimethylformamide:33% water. The selenols react rapidly to form stable dinitrophenyl (DNP) selenoethers that can be extracted into benzene; these are easily identified by TLC, HPLC, or mass spectrometry. Hydrogen selenide is trapped in 90–99% yield, primarily as the di-DNP-monoselenide with a trace of di-DNP-diselenide.