Liquid chromatographic-mass spectrometric analysis of N-acetylamino acids in human urine.

K Sugahara, J Zhang, H Kodama

Index: J. Chromatogr. B, Biomed. Appl. 657(1) , 15-21, (1994)

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Abstract

Liquid chromatography-atmospheric pressure chemical-ionization mass spectrometry (LC-APCI-MS) was used for the analysis of N-acetylamino acids that could not be determined with an amino acid analyzer. LC-APCI-MS could directly detect the protonated molecular ions of various synthetic N-acetylamino acids, distinguishing N-acetylserine from O-acetylserine and N(alpha)-acetyllysine from N(epsilon)- acetyllysine. Furthermore, N-acetylasparagine, N-acetylaspartic acid, N-acetylglutamine and N-acetylglutamic acid were identified in normal human urine. The assay data for N-acetylaspartic acid agree with a previous report using gas chromatography-mass spectrometry. These results demonstrate the usefulness of the apparatus described above for the analysis of N-acetylamino acids in biological samples.