Optimization of Adsorptive Stripping Voltammetry Procedure Using Chloranilic Acid as a Complexing Agent for the Determination of Ultra-Trace Germanium in NaturalWater Samples

For the first time chloranilic acid was used as a complexing agent in the adsorptive stripping voltammetric method to perform trace determination of germanium. As an example of the proposed procedure the ultra-trace Ge(IV) determination in environmental samples, such as river and lake water samples was carried out. The composition of the supporting electrolyte as well as the influence of accumulation potential and time on the germanium voltammetric signal were verified. The method is based on cathodic adsorptive stripping voltammetry of the Ge(IV)-chloranilic acid complex at a renewable mercury film silver based electrode (Hg(Ag)FE). The calibration graph was linear from 5 x 10(-10) to 2 x 10(-7) mol L-1 with a detection limit calculated as 1.67 x 10(-10) mol L-1 for a deposition time of 30 s. The influence of interfering substances such as foreign ions, EDTA, surfactants and humic substances present in the matrices of natural water samples on the Ge(IV) signal was precisely examined and the satisfying minimization of these interferences was proposed. (c) 2017 The Electrochemical Society. All rights reserved.