Application of a central composite design to the determination of inorganic and liquid chromatography–hydride generation–atomic absorption spectrometry

Resumen

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 24+* was used in the optimization of analytical conditions for the arsenic speciation method. The variables
investigated were (A) mobile phase flow rate, (B) HCl concentration, (C) KI 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.