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-cystathionine in biological samples has been developed by using column liquid chromatography-mass spectrometry. The concentrations of cystathionine and NAc-cystathionine in urine, several tissues, and serum of propargylglycine-treated rats with experimental cystathioninuria were determined by scanning the [M + H]+ ions of each compound. The recoveries of authentic compounds were 95.69 +/- 4.44% (n = 10) for cystathionine and 91.59 +/- 5.26% (n = 10) for NAc-cystathionine after ion-exchange resin treatment. The contents of cystathionine and NAc-cystathionine in the urine of a patient with cystathioninuria were also measured. The results coincided well with those obtained using an amino acid analyzer.