Investigation of two fluorinated reagents for the analysis of selenium by gas chromatography.

As potential reagents for the determination of traces of selenium by gas chromatography, the compounds 4-fluoro-o-phenylenediamine and 4-trifluoromethyl-o-phenylenediamine have been examined and compared with seven o-diamines previously reported for analytical purposes. Retention times of the fluoro-piaselenols are shorter than all other compounds but, with the electron-capture detector, their responses differ widely. However, the detection limit of the trifluoromethylpiaselenol compares favourably with the commonly used derivative, 5-nitropiaselenol. The analytical requirements of 4-trifluoro-o-phenylenediamine as a reagent, and the results of its application to the determination of selenium in various biological matrices, are presented.