Dual-channeled capillary electrophoresis coupled with contactless conductivity detection for rapid determination of choline and taurine in energy drinks and dietary supplements

Abstract

In this study is reported a simple and inexpensive method for concurrent determination of taurine and choline in different supplementary nutrient samples using dual-channeled capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C⁴D). The objective of the work is to propose a tool for food control activities that allows screening of different target compounds (having different characteristics) in a single run for high throughput and can be realizable even with modest infrastructure. Taurine was analyzed in the first CE channel using the background electrolyte (BGE) composed of 150 mM tris(hydroxymethyl)aminomethane/lactic acid (pH 8.96) whereas choline was simultaneously separated in the second CE channel using a BGE containing 150 mM tris(hydroxymethyl)aminomethane/acetic acid (pH 9.5). The best achieved detection limit was 0.27 mg/L and 0.45 mg/L for taurine and choline, respectively, using the developed CE-C⁴D method. Good agreement between results obtained from CE-C⁴D and those with the standard confirmation methods (HPLC-DAD for taurine and LC/MS for choline) was achieved, with the result deviation for the two pairs of data being less than 12%.

Keywords: Capacitively coupled contactless conductivity detection (C(4)D); Capillary electrophoresis (CE); Choline; Food control; Taurine.