[Simultaneous determination of 18 amino acids by reversed-phase high performance liquid chromatography with precolumn phenylisothiocyanate derivatization].

A reversed-phase high performance liquid chromatographic method for simultaneous determination of 18 amino acids is described. The sample was mixed with norleucine as the internal standard, then derivatized with phenylisothiocyanate (PITC) and analyzed on a Kromasil C18 column at 38 degrees C, using gradient elution with detection at 254 nm. The correlation coefficients between the ratios of peak area of amino acid to that of the internal standard and the amino acid concentrations were above 0.99, except for cysteine(Cys)(0.962). The recoveries of amino acids added were 96.0%-102.4%. Detection limit of leucine was 0.5 mg/L. The method was applied to analyze free amino acids in deproteinized calf blood injection and good results were obtained.