Total iron determination in drinking water using stripping voltammetry technique

Abstract

The paper describes the development and optimization of an analytical technique based on stripping voltammetry for iron determination in drinking water. The method is based on AdSV technique and HMDE electrode. Along with the complexing agent, the catechol, a pH buffering phosphate solution (pH 7) is added. The reference electrode is Ag/AgCl/KCl. The principle of the method is the following: iron complexation by the catechol, adsorption of the complex on the drop of the electrode followed by the stripping stage and practical resolubilization of the complex. Two concentration ranges were tested: from 10 to 50µg/L and between 25 and 150µg/L. After calibration curves were plotted, real drinking water samples enriched with iron standard solution were analysed. Laboratory test results indicate a very good recovery rate for the analytical trials performed (100.44%, 104.07%, 103.49%). However, the average value of the recovery rate following all aditions and replicates – the precision grade is 102.66%. The correlation factor between the two curves was 0.9936 for the interval of 10- 50µg/l and 0.9989 for the interval of 25-150µg/L. The optimised method can be easily applied in case of drinking water resources both surface and underground water.