Analytical method to evaluate taurine in energy drinks after o-phthalaldehyde-ethanethiol derivatization using square wave voltammetry

Abstract

A completely new voltammetric method has been developed for quantitative determination of food additive Taurine (Tau) in energy drinks. This electroanalytical method is based on voltammetric oxidation of o-phthalaldehyde-ethanthiol derivative of Tau at glassy carbon electrode in 95% methanol containing 0.1 mol L-1 lithium perchlorate. Working conditions necessary for quantitative Tau derivatization reaction and electrochemical detection using square wave voltammetry were optimized. Linear range from 1.0×10 5 to 1.0×10 4 mol L-1 characterized by coefficient of determination 0.9998, limits of quantification 6.81×10 6 mol L-1 and detection 2.07×10 6 mol L-1 were obtained at pulse amplitude 50 mV and frequency 80 Hz. Analytical method of calibration curve was used for monitoring of Tau in several commercially available energy drinks. The procedure was validated using standard reference high performance liquid chromatography (HPLC) method.