Direct and simultaneous determination of amino acids and sugars in rice wine by high-performance anion-exchange chromatography with integrated pulsed amperometric detection

Abstract

A method for direct simultaneous determination of amino acids and sugars, including monosaccharides, disaccharides, trisaccharides, and tetrasaccharides, in rice wine by high-performance anion-exchange chromatography with integrated pulsed amperometric detection is described. The mobile phase gradient was prepared from aqueous solutions of sodium hydroxide and sodium acetate. The effects of mobile-phase composition and column temperature on the separation of the amino acids and sugars were investigated in detail and optimized conditions were determined for analysis of amino acids and sugars in rice wine. The time taken to run the gradient was 90 min. The column temperature was 30°C. Amino acids and sugars in the rice wines were identified by using two different waveforms and comparing the results from each. Under the optimized conditions detection limits for the amino acids and sugars were 0.11–12.80 pmol.RSD of peak areas were 0.3–3.7% (n=5). Calibration graphs of peak area for the analytes were linear over approximately three orders of magnitude. Ten amino acids and eight sugars in rice wine were identified and quantified. Recoveries of these components after spiking were 95.4–105.8%. Chromatograms obtained from rice wine under optimized gradient conditions were used for rough assessment of the quality of the wine.