Development of capillary electrophoresis method to determine the content of major free amino acids in commercial royal jelly products

Abstract

Royal jelly contains a lot of valuable nutrients with several kinds of amino acids which are important to the development of human body. This study presented the development of the analytical method based on capillary electrophoresis (CE) using capacitively coupled contactless conductivity detector (C⁴D) for determination of five major free amino acids in royal jelly products including lysine (Lys), alanine (Ala), proline (Pro), glutamic acid (Glu), and aspartic acid (Asp). Five amino acids were separated in a capillary with an effective length of 48 cm and in 2M lactic acid electrolyte. At the optimised conditions, the linear ranges of calibration curves were from 2.0 to 100 mg/l, and the linearities were good (R² >0.999). The method had good accuracy with the recoveries in range of 93÷115% for deionised water and real sample matrixes. The procedure has been successfully applied to the determination of five major free amino acids in commercially available royal jelly products