Rapid determination of selenium in various substrates by electron capture gas-liquid chromatography.

In the proposed procedure for the determination of selenium, 0.5-1 g of sample is wet ashed with concentrated nitric acid. After adding 1,2-diamino-4,5-dichlorobenzene to the digest at pH 1, the resulting dichloropiazselenol derivatives is extracted with toluene. The extract is purified by column chromatography over Florisil and analyzed by gas-liquid chromatography with electron capture detection. Recoveries of selenium added to various substrates ranged from 72 to 102%. The limit of detection is approximately 0.01 ppm, but smaller amounts can be determined by increasing the sample size or by concentration of the final extract.