Direct,Continuous Hydride Generation Coupled with Microwave Induced Plasma-Atomic Emission Spectrometry for the Determination of Selenium

Selenium is determined by atomic emission technique with microwave induced helium plasma as the excitation source. A continuous hydride generation system using a peristaltic pump, an effective serpentine hydride generator and a gas-liquid separator is developed and interfaced to the He-plasma. The selenium hydride and the reaction by-products are carried directly and continuously by the He carrier gas (0.6 L/min) into the plasma sustained in a tangential torch. The power level is 100 W and the tangential helium flow-rate is 4.5 L/min. The detection limit (3 0) is 40 ppb, the linear dynamic range is over three orders of magnitude, and the precision is 6.7% RSD for a 1 ppm solution. Applications to a soil sample showed comparable results to a conventional hydride generation atomic absorption system.