Application of hydride generation to the determination of trace concentrations of arsenic by capacitively coupled microwave plasma

Studies are presented describing an application of the NaBH4 reduction of soluble arsenite to form arsine for ultra-trace level arsenic determination by capacitively coupled microwave plasma atomic emission spectrometry. The arsine was condensed in a liquid nitrogen cooled trap, and introduced into the plasma after the elimination of reaction by-products that would reduce the excitation efficiency of the plasma. Use of a photodiode array detector provided a means of background correction. The procedure resulted in a limit of detection of 110 pg and linear dynamic range of 104 for arsenic.