engleski

Diffrent electrophoretic approaches in the determination of L-Carnosine in commercial dietary supplement formulations

Introduction: Nowadays, an incredible variety of dietary supplements are available on the market. Frequently used types of dietary supplements are those that contain amino acids, peptides, or proteins. One of the substantial peptides used among athletes is L-carnosine, which improves endurance during intense exercise and has potential application in disease treatments. However, the safety of supplement products is questionable because of weak law regulations regarding their content. The main drawbacks of commonly utilized methods are high prices, complex and time-consuming sample preparation and analysis. Therefore, there is a demand to develop a new approach for fast, cheap, and simple analysis of amino acids, peptides, and proteins. Aim: The first part of the investigation included the primary objective of the study, that was development of cheap, fast, simple and environmentally friendly method for determination of L-carnosine in dietary supplements on innovative microchip electrophoresis (ME) technology. In the second part of the study, the samples were analyzed by capillary electrophoresis (CE) - ultraviolet–visible (UV-VIS) detection to compare these two electrophoretic methods in case of dipeptide determination in real samples. Method: ME analysis was performed on a double-T poly(methyl methacrylate) chip (ChipShop GmbH) MCE devise model ET121 (eDAQ) that incorporated ER430 High Voltage Sequencer (HVS) and ER225 C4D system. CE analysis were performed on Agilent Technologies 7100 CE instrument. Results: Linear detection range were tested from 2.5 × 10-6 to 2.5 × 10-5 M (R2 = 0.9801) for C4D and from 4.4 × 10-4 to 4.4 × 10-3 M (R2 = 0.9905) for UV-VIS. The separation was faster using ME-C4D due to the relatively low retention time on the microchip, which was only 73 s for L-carnosine. In the case of utilizing CE-UV- VIS, the migration time was 13.4 min. Conclusions: The determination of L-carnosine in two different commercial dietary supplements was accomplished using ME-C4D and CE-UV-VIS methods. Both methods showed insignificant deviations from the labeled concentration of L- carnosine. However, ME-C4D showed slightly lower detection limits and analysis time. Both methods proved to be environmentally friendly, moreover, ME-C4D provided lower sample and buffer consumption.

L-carnosine ; microchip electrophoresis ; capacitively coupled contactless conductometry detection ; capillary electrophoresis ; UV-VIS detection

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