Determination of amino acids and glucose in amino acid injection by anion exchange chromatography with integrated pulsed amperometric detection

A direct, sensitive, simple and practical method for the determination of amino acids and glucose in amino acid injection by anion exchange chromatography with integrated pulsed amperometric detection was developed. There is no need for sample pretreatment. The retention behavior of amino acids and glucose on the anion exchange column was investigated using sodium hydroxide and sodium acetate as eluent. When the concentration of sodium hydroxide was changed, the change in the retention times was generally greater for amino acids than for glucose. The difference can be used to improve the separation between amino acids and glucose. When the concentration of sodium acetate was changed, the change in the retention times was generally greater for amino acids containing two carboxyl groups than for amino acids containing only one carboxyl group. The difference can be used to improve the separation between di carboxylic amino acids and mono carboxylic amino acids. In order to separate amino acids and glucose, a ternary gradient elution method with water, sodium hydroxide and sodium acetate as mobile phases was employed. The optimized gradient elution condition for the analysis of 17 amino acids and glucose in amino acid injection was obtained. The time of the gradient elution program was 74 min. Under the optimized conditions and the column temperature of 30 ℃, the detection limits for 17 amino acids and glucose were 0 3 pmol-10 3 pmol. The calibration graphs of peak area for all the analytes were linear in the ranges about two orders of magnitude. The relative standard deviations (RSDs) ( n =5) were 0 7%-3 8%. The recoveries of added standard were 88 3%-104 6%.