Inexpensive and simple tool for quality control of nutraceutical and tonic products with capillary electrophoresis and contactless conductivity detection: Some developments in Vietnam

In this study, we report the development of versatile and cost-effective analytical approaches for analysis and quality control of different nutraceutical and tonic products, using capillary electrophoresis (CE) coupled with contactless conductivity detection (C4D). Insights into CE-C4D instrumental designs that are adapted to the context in developing countries are provided. A highlight was made for quality control of vitamins, glucosamine and some minerals in different nutraceutical formulations collected from pharmacies in Vietnam. The lowest detection limit (LOD) achieved with the developed methods was 0.1 mg/L for vitamins, using the optimized background electrolyte (BGE) composed of 12 mM arginine (Arg)/acetic acid (AcOH) at pH 7.5 with 10 % acetonitrile (ACN). For magnesium and B6, the optimized CE-C4D conditions with the BGE composed of 10 mM Arg/AcOH (pH 5) with 20 % ACN allows its detection down to 0.05 mg/L. For glucosamine and calcium, the best performance with LOD of 0.05 mg/L was achieved with BGE composed of 10 mM Tris/AcOH (pH 5). Good agreement between results from CE-C4D and the confirmation methods was achieved for all investigated compounds, with their result deviations less than 15 %.