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Determination Of Inorganic Selenium Species In Water Sample By Flow Injection AAS Coupled With Derivative Signal Processing

Jing Ha, Han-wen Sun, Wei-jun Kang

An on-line sand bath heating prereduction of Se (VI) to Se (IV), has been coupled with hydride generation atomic absorption spectrometry with derivative signal processing for final detection for Se (IV) and Se (VI) in water samples. The samples and the prereductant solutions which circulated in a closed-flow circuit were injected by means of a timebased injector. When using 10mV min-1 sensitivity grade of the derivative system, the linear ranges were 0-80 μg l-1 for Se (IV) and Se (VI). The detection limit was 0.102 μg l-1 . The precision (about 1.2-4.1%RSD) was good. The continuous flow system for selenium determination allows a high sample throughout (about 30 samples h-1) in which high automation can be achieved and constitutes a convenient real-time continuous detector with high sensitivity for the selenium tested. The method was applied to the determination of inorganic selenium in river water and tap water, the recoveries are between 97-102%.