Determination of Selenium(IV, VI) by Heated Quartz Cell Atomic Absorption Spectrometry with Miniaturized Suction-Flow On-Line Prereduction/Hydride Generation System

摘要

The development and optimization of a miniaturized hydride generation system for atomic absorption spectrometry of selenium(IV, VI) by suction-flow on-line prereduction of selenium(VI) to selenium(IV) are described. A discrete aqueous sample is sucked into a concentrated hydrochloric acid line and brought to the prereduction coil (95°C) by a peristaltic pump. Then the mixture and sodium tetrahydroborate solution are delivered by the pump to gas-liquid separators. The evolved hydrogen selenide is swept into an electrically heated quartz cell of an atomic absorption spectrometer. A transient absorption signal is recorded on a strip chart recorder. The 3σ detection limit is 0.7ng cm-3 selenium and the calibration is linear up to 30ng cm-3 with 1cm3 sample solution. The relative standard deviation (n=10) is 3.0% for 25ng cm-3 selenium. The sample throughput is 30h-1. Results of analysis of some certified biological reference materials are given.