Study on simultaneous measurements of trace gallium(III) and germanium(IV) by adsorptive stripping voltammetry using mercury film electrode

Simultaneous adsorptive stripping voltammetric method for the determination of trace gallium(III) and germanium(IV) based on the adsorption of gallium(III) and germanium(IV)-catechol complex on the cyclic renewable mercury film silver based electrode (Hg(Ag)FE) is presented. The calibration graph is linear from 1.25 nM (0.09 mu g L(-1)) to 90 nM (6.27 mu g L(-1)) with correlation coefficient of 0.999 for gallium and from 2.5 nM (0.18 mu g L(-1)) to 160 nM (12.3 mu g L(-1)) with correlation coefficient of 0.998 for germanium for a preconcentration time of 30 s. The detection limit for a preconcentration time of 60 s is as low as 25 ng L(-1) for gallium and 58 ng L(-1) for germanium. The proposed method was successfully applied by studying the natural samples and simultaneous recovery of Ga(III) and Ge(IV) from spiked water and sediment samples.