Continuous flow vapor generation for inductively coupled argon plasma spectrometric analysis. Part 1: Selenium.

Total selenium is determined by inductively coupled plasma (ICP) atomic emission using hydride vapor generation. A 1 g sample is wet ashed in a 16 x 150 mm 10 mL volumetric test tube on a programmed heating block with nitric, sulfuric, and perchloric acids at up to 310 degrees C. After treatment with hydrochloric acid, the selenium is reduced by sodium borohydride to hydrogen selenide is a simplified continuous flow manifold. A standard pneumatic nebulizer effects the gas-liquid separation of H2Se, which is quantified by ICP atomic emission at 196.090 nm. The instrument detection limit for the method has been determined to be 0.4 microgram/L. For a 10:1 dilution of a nominal 1 g sample, the detection limit is 4 micrograms/kg and the linear range is up to 4 mg/kg. The method has demonstrated statistical control for samples of biological and environmental interest and is especially well suited to analysis of small samples.