DETERMINATION OF AMINO-ACIDS BY PRECOLUMN DERIVATIZATION WITH 6-AMINOQUINOLYL-N-HYDROXYSUCCINIMIDYL CARBAMATE AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ULTRAVIOLET DETECTION

A precolumn derivatization method for the determination of amino acids using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) followed by high-performance liquid chromatography is described. Ultraviolet de tection was used for the assay of AQC derivatives of amino acids with the detection wavelength set at 248 nm. The reagent peak interference was minimized by optimizing the pH of the eluent and the gradient elut ion profile to improve the resolution between the reagent peak and ami no acid derivatives. All nineteen amino acids were separated in 35 min with resolutions greater than or equal to 1.6. The correlation coeffi cients of the calibration graphs for seventeen amino acids were fairly good (r greater than or equal to 0.9999) at concentrations of 25-500 mu M. The detection limits for all common amino acids including cystin e and tryptophan were at the range 0.07-0.3 pmol. Good reproducibility and accuracy of the method were demonstrated by the determination of amino acids in three typical kinds of samples (protein, peptide and fe ed). The average relative standard deviations for bovine serum albumin (BSA) and neuromedin were 0.86% and 1.36, respectively, and the avera ge relative errors were 3.2% and 2.3%, respectively. The results of th e analysis of feed hydrolysates agreed with those obtained by an ion-e xchange method and the average recovery of the method for feed hydroly sates was 98%.