Gas chromatographic-mass spectrometric detection of S-nitroso-cysteine andS-nitroso-glutathione

A gas chromatographic-mass spectrometric (GC-MS) method is described for th e quantitative determination of the S-nitroso compounds S-nitroso-cysteine (SNC) and S-nitroso-glutathione (GSNO) using their N-15-labeled analogs, i. e., (SNC)-N-15 and GS(15)NO, as internal standards. The method is based on the specific conversion by HgCl2 of the unlabeled and N-15-labeled S-nitros o groups to nitrite and N-15-nitrite, respectively, and their conversion to the pentafluorobenzyl derivatives. The method was applied to quantify GS(1 5)NO formed in the cytosol of washed human erythrocytes incubated with (SNC )-N-15. Combination of high-performance Liquid chromatography with GC-MS al lowed specific and accurate quantification of SNC and GSNO externally added to human plasma ultrafiltrate (range 0-10 mu M). Method accuracy and preci sion for SNC and GSNO were close to 100 and below 9%, respectively. As litt le as 0.1 nM GS(15)NO corresponding to 30 amol of N-15-nitrite injected ont o the column was precisely detected by the method. (C) 1999 Academic Press.