Selection of Optimal Ligand and Vanadium(IV) Complexonate for Sensitive Catalytic Adsorptive Stripping Voltammetric Quantification of Germanium

The study describes the properties of catalytic adsorptive stripping voltammetric (CAdSV) systems based on complexes of Ge(IV) with gallic acid, catechol or pyrogallol as well as vanadium complexes with complexones such as NTA, DHPTA, EDTA, and HEDTA, used as catalytic agents. The most pronounced CAdSV response was observed when the Ge(IV)-pyrogallol complex was coupled with V(IV)-HEDTA. In 0.05 M of acetate buffer containing 1 mM of pyrogallol, 2 mM of V(IV) and 4 mM of HEDTA, the peak current of germanium exhibited good linearity for Ge(IV) concentrations over the range from 0.25 nM to 25 nM and a low limit of detection (LOD=0.02 nM). The method was verified by measuring Ge(IV) in real water samples.