SIMULTANEOUS DETERMINATION OF INORGANIC ARSENIC(III) AND ARSENIC(V) BY ARSINE GENERATION AND GAS-PHASE MOLECULAR ABSORPTION SPECTROMETRY

A method for the simultaneous determination of inorganic As(III) and As(V) is described, which involves arsine generation, measurement of the molecular absorption of arsine in the gas phase at 190 nm and quantification of As(III) and As(V) based on different heights and areas of absorbance versus time profiles of arsine generated from both inorganic species. The limits of detection were 0.5-mu-g of As(III) and 3-mu-g of As(V) in a sample volume of 1 ml. An interference study for both species was made and the method was applied to the determination of As2O3 and As2O5 in a standard glass sample.