Bismuth film electrode and chloranilic acid as a new alternative for simple, fast and sensitive Ge(iv) quantification by adsorptive stripping voltammetry

Abstract

An analytical procedure regarding the voltammetric determination of germanium(IV) by adsorptive stripping voltammetry (AdSV) exploiting the in situ plated bismuth film electrode (BiFE) is described. The use of mercury free electrode as a working electrode is the first time proposed in AdSV germanium determination. The method is based on adsorptive accumulation of the Ge(IV)–chloranilic acid complex at a BiFE by a nonelectrochemical process followed by the cathodic stripping step. Experimental variables, including bismuth and chloranilic acid concentrations, deposition potential and time were carefully optimized. Under optimized conditions the cathodic stripping peak current was directly proportional to the concentration of Ge(IV) in the range from 3 × 10⁻⁹ to 1.5 × 10⁻⁷ mol L⁻¹ with the correlation coefficient 0.997. Because the AdSV technique could be invalidated due to real samples matrix the influence of foreign ions, surface active substances, and humic substances on the Ge(IV) signal was precisely examined. The satisfying minimization of potential matrix interferences was also suggested. Analytical results of natural water samples analysis showed that the proposed procedure of trace germanium(IV) determination is suitable for direct environmental water analysis.