Application of a central composite design to the determination of inorganic and organic arsenic species in water by liquid chromatography-hydride generation-atomic absorption spectrometry

摘要

An on-line high performance liquid chromatography - hydride generation atomic absorption spectrometry coupled system (HPLC-HG-AAS) has been used for the determination of [As (III)], [As (V)], monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in water samples. Four variables were taken into account and a central composite design 2~(4+~*) was used in the optimization of analytical conditions for the arsenic speciation method. The variables investigated were (A) mobile phase flow rate, (B) HCI concentration, (C) Kl concentration, (D) NaBH4 concentration. Individual factors (A) and (B) were the most significant effects, and the optimum conditions for all factors were A = 1.2 mL min~(-1) B = 2.8 mol L~(-1) C = 1.7 % w/v, and D = 1.4 % w/v. The repeatability, stability, calibration curve and limit of detection were established. The method was applied to different kinds of waters; good recoveries of added spikes (92 - 109 %) were obtained for all analytes.