Collect. Czech. Chem. Commun. 1998, 63, 2027-2035

The Use of a Membrane GasLiquid Separator for Flow Injection Hydride Generation Atomic Absorption Spectrometry On-Line Speciation and Determination of As(III) and As(V)

Milan Krenželok and Petr Rychlovský

Department of Analytical Chemistry, Charles University, 128 40 Prague 2, Czech Republic


This method employs a membrane gas-liquid separator and the hydride generation technique in the FIA AAS method for speciation of As(V) and As(III). The gas-liquid membrane separator achieves high measurement sensitivity and shows a very fast response (short delay time) because of its minimum dead volume. Conditions were optimized for the determination of arsenic by the flow injection hydride generation atomic absorption spectrometry method using this membrane separator. An apparatus was proposed for on-line speciation of both As(V) and As(III). Several reduction systems were used for reduction of As(V) to As(III) in the on-line arrangement. The best results were obtained using solution of 15 g KI in 100 ml of 6 M HCl at the reaction coil temperature 60 °C. A detection limit of 150 pg for As(III), 80 pg for As(III + V) and sampling rate of 25 samples per hour were reached.

Keywords: Speciation; Arsenic; Gas-liquid separator; Hydride generation; AAS; FIA.