Application of capillary electrophoresis for assessing amino acids composition of Jujube from different geographical origins

Abstract

A simple capillary electrophoresis (CE) method that using β-cyclodextrin (β-CD) as buffer modifier has been developed for the detection of ten amino acids of jujube from five different geographical origins. The CE methodology was optimized through the variation of type, pH and concentration of the buffer solution, concentration of the additive β-CD, applied voltage, injection time and wavelength of the UV detection. It was found that the best separation of ten kinds of amino acids was achieved within less than 6 min under the optimum separation conditions: 50 mmol L-1 pH 9.5 borate-phosphate buffer with 5.0 mmol L-1 β-CD, 15 kV applied voltage, 25 °C column temperature, 210 nm detection wavelength, and 5 s injection time. This method showed good repeatability with RSD values of 1.4-3.4% for peak area, and 1.4-4.7% for migration time, when β-CD was used as buffer modifier. Under the optimum conditions, the method has been successfully applied to the detection of actual jujube samples, which also verifies the effectiveness and practicability of the method. Recovery of real samples was in ranging of 90%-105%, which proved the feasibility of the method. It also proved that the method was successfully applied to the quantitative analysis of amino acids of interest in plant samples.