engleski

Development of new microchip electrophoresis method for detection of β-alanine and L-histidine in dietary supplements

The use of dietary supplements has become a part of everyday life. Due to their wide application, there is a variety of dietary supplements on the market. Amino acid-containing dietary supplements are often consumed among athletes. For example, L- histidine and β-alanine containing dietary supplements are used to improve endurance during intense exercise. The content of dietary supplements is not strictly regulated by law. Therefore they are not analyzed in such a strict manner like drugs. This can lead to the questionable quality of these products and potential health risks for consumers. Standard methods for the analysis of individual amino acids have some disadvantages. Hence, there is a demand to develop an alternative analytical method for analyzing amino acids in dietary supplements. Thus, this study investigates microchip electrophoresis (ME) conjugated with a capacitively coupled contactless conductivity detector (C4D) for analysis of complex dietary supplement formulations. Three types of dietary supplements were tested ; tablet, capsule, and powder. As the primary active substance, tablets and powder contained L-histidine and capsules contained β-alanine. The obtained concentrations were in good agreement with the data declared on the labels. Successful separation was achieved within 38 (±0.2) s for L-histidine and 26 (±1) s for β-alanine. A linear relationship between C4D detector response and β-alanine concentration was assessed in the range 10 - 100 µmol L-1 (R2 = 0.9954) and in the range of 10 - 100 µmol L-1 (R2 = 0.9968) for L-histidine, respectively. The limits of detection of both L-histidine and β- alanine were below mgL-1. The results show the potential application of the proposed method for fast and cheap analysis of L-histidine and β- alanine in a dietary supplements. Moreover, the method is environmentally friendly, uses a minimal volume of samples and solvent and offers opportunities for integration and automatization of multiple analytical steps.

aminokiseline ; analitička kemija ; kapacitivno spregnuti beskontaktni konduktometrijski detektor ; zeleno ; laboratorij na čipu ; separacija

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