Determination of Selenium inGeochemical Samples by Flow Injection Hydride Generation Inductively Coupled Plasma Atomic Emission Spectrometry Following On-line Removal of Iron Interference by Anion Exchange

Abstract

Selenium was determined in geological samples with a high content of iron by HG–ICP-AES in combination with flow injection (FI) on-line iron separation. Anion-exchange separation with hydrochloric acid was applied for the separation of selenium from iron. The iron–chloro complexes were adsorbed on an anion-exchange (Dowex 1X-8) microcolumn (3.0 mm id×50.0 mm bed length), while the analyte was introduced into the hydride generation system. After the removal of the iron, a 700 µl sample was injected into a water carrier stream. This was merged with hydrochloric acid and sodium tetrahydroborate in order to generate selenium hydride. The system was found to have a limit of detection of 0.3 ng ml -1 and an RSD of 2% for a 20 ng ml -1 selenium concentration. The application of the method to geochemical standard reference samples (GSD-4, GSS-7, GSR-6, JB-2 and JGb-1) demonstrated that the results were statistically indistinguishable from the certified values.