Determination of amino acids in human blood serum by reversed-phase high-performance liquid chromatography in the isocratic elution mode

A procedure is developed for the determination of 15 amino acids in human blood serum using ortho-phthalic aldehyde in combination with 2-mercaptoethanol or sodium sulfite as the reagent for the precalumn synthesis of derivatives with their subsequent separation by reversed-phase high-performance liquid chromatography in the isocratic elution mode using electrochemical detection. Conditions of the quantitative conversion of amino acids to corresponding derivatives were determined; ortho-phthalic/2-mercaptoethanol and ortho-phthalic/sulfite derivatives of amino acids are stable during the whole cycle of analysis. The total time of separation is 80 min. The detection limits are 0.5-5 pmol (at the signal-to-noise ratio equal to 2). The procedure is used for the determination of glutamic acid, asparagine, serine, glutamine, histidine, taurine, alanine, arginine, methionine, isoleucine, ornithine, leucine, phenylalanine, lysine, and tryptophane in blood serum of healthy donors and of sick with alcoholism before: and after treatment.