SIMULTANEOUS DETERMINATION OF CYSTATHIONINE AND NAC-CYSTATHIONINE USING LIQUID-CHROMATOGRAPHY ATMOSPHERIC-PRESSURE CHEMICAL-IONIZATION MASS-SPECTROMETRY

A method for simultaneous determination of cystathionine and NAc-cysta thionine in biological samples has been developed by using column liqu id chromatography-mass spectrometry. The concentrations of cystathioni ne and NAc-cystathionine in urine, several tissues, and serum of propa rgylglycine-treated rats with experimental cystathioninuria were deter mined by scanning the [M + H](+) ions of each compound. The recoveries of authentic compounds were 95.69 +/- 4.44% (n = 10) for cystathionin e and 98.59 +/- 5.26% (n = 10) for NAc-cystathionine after ion-exchang e resin treatment. The contents of cystathionine and NAc-cystathionine in the urine of a patient with cystathioninuria were also measured. T he results coincided well with those obtained using an amino acid anal yzer. (C) 1995 Academic Press, Inc.