Automated derivatization with o-phthalaldehyde for estimation of amino acids in plasma using reversed-phase high performance liquid chromatography.

A fully automated method for quantitative estimation of plasma amino acids using fluorescence detection of ophthaladehyde/2-mercaptoethanol derivatives of the analytes and their separation by gradient elution reversed-phase HPLC has been described. The method is simple and the three-step gradient elution is suitable for routine analysis of a large number of biological samples due to clear resolution, high degree of precision, accuracy, cost-effectiveness and lack of interference from chemical contaminations. Using this method, 19 amino acids were completely resolved and the within-run coefficients of variation ranged from 2.53 to 10.7% with a mean variation of 5.68%.