Liquid Chromatographic and Spectrophotometric Determination of Taurine in Energy Drinks Based on O-Phthalaldehyde-Sulfite Derivatization

Abstract

Rapid and efficient high-performance liquid chromatographic and UV-Vis spectrophotometric methods have been optimized and validated for taurine determination in energy drinks. Taurine was derivatized with o-phthalaldehyde and sodium sulfite in alkaline media prior to analysis. The optimum derivatization parameters were found to be 0.1 M borate buffer at pH 9.5, reaction time 5.0 min, o-phthalaldehyde concentration of 60 mg L-1 , sodium sulfite concentration of 202 mg L-1 and water as diluting solvent. The analytical parameters such as linearity, limit of detection (LOD), limit of quantification (LOQ), precision and accuracy were investigated. The methods were linear in range 0.5-20 mg L-1 and 0.5-15 mg L-1 with correlation coefficient (r 2) of 0.9998 and 0.9996 for HPLC-PDA and spectrophotometer respectively. The LODs were 0.109 mg L-1 and 0.141 mg L-1 for HPLC-PDA and spectrophotometer respectively. The precision (RSD%) of intra-day and inter-day of the methods were 1.816-1.278% and 2.858-2.236% respectively, for HPLC-PDA and spectrophotometer respectively. Recoveries of taurine ranging from 90% to 105%, (n = 3) were obtained. The methods were successfully applied for determination of taurine in energy drink samples.