Adsorptive stripping voltammetry of vitamin D3 at glassy carbon electrode

Abstract

Adsorptive stripping voltammetry (AdSV) of cholecalciferol at the glassy carbon electrode (GCE) was developed and based on existing conventional approaches employing anodic oxidation in pure organic electrolytes or aqueous-organic mixtures. Despite a rather poor reproducibility of the adsorption-driven process (with the RSD of ca. 10 %), significantly higher sensitivity was achieved. As optimum conditions, the respective procedure comprised an accumulation of cholecalciferol from 40% ethanol at 300 min–1 for 8 min followed by electrochemical detection in the Britton-Robinson buffer (pH 4.0) using square-wave voltammetry at a potential step of 5 mV, amplitude of 35 mV, and frequency of 40 Hz