DETERMINATION OF ARSENIC AND SELENIUM IN RIVER WATER BY HYDRIDE GENERATION ICP-AES

As and Se hydride, generated in a mixing coil, was collected in a gas- liquid separator which is sealed with an electromagnetic pinch valve. The hydride formed was swept continuously into the torch of an inducti vely coupled plasma atomic emission spectrometer. The system was opera ted with variable-speed peristaltic pumps by manipulating electromagne tic relays and a timer. Interferences with transition metals were elim inated by elution with Chelex 100 resin. Detection limits (3 times the signal-to-noise ratio) of arsenic and selenium were 0.3 and 0.6 ng/mL , respectively. The accuracies, verified using biological standard ref erence materials, were obtained from the National Institute of Standar ds and Technology (NIST), USA, and the National Research Council (NRC) , Canada, and are within the certified values, except for the Oyster T issue.