Determination of Total Selenium in Soil by Atomic Fluorescence Spectrometry with Program Temperature-Controlled Graphite Digestion

A program temperature-controlled graphite digestion method was developed and used in the determination of total selenium in soil using atomic fluorescence spectrometry(AFS). Digestion fluid, digestion temperature, digestion time and digestion procedure were determined. Working conditions of hydride generation-atomic fluorescence spectrometer (HG-AFS) and optimal hydrogenation reaction conditions were found under which satisfactory analytical results were obtained. The linear range was 1~10 μg/L, the detection limit of selenium was 0.15 μg/L, the relative standard deviation was 3.2% , and the recoveries were 92%~108%. The advantages of this method include simple operation, short digestion time, small amount of digestion fluid, automatic digestion process, high precision, high accuracy, greatly reduced labor intensity and physical harm for users. It is particularly suitable for the rapid determination of large quantities of soil samples.