FLOW-INJECTION ANALYSIS AND CONTINUOUS-FLOW SYSTEMS TO DETERMINE AS(III) AND AS(V) BY HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY

A method for the determination of total arsenic and inorganic As(III) and As(V) by either FIA or continuous flow hydride generation-AAS is r eported. If AsH3 is generated in 6 M HCl, the addition of KI to reduce As(V) to As(III) is not required. The precision of arsine generation in 6 M HCl or citric/citrate medium is higher in the continuous flow s ystem than in the FIA system. The detection limits in 6 M HCl medium a re reported for 0.75 ng of As(III) in FIA and for 4.5 ng ml(-1) of As( III) in continuous flow. The proposed method has been applied to drink ing waters and the total arsenic determination has been validated for water analysis by a laboratory intercomparison study.