Identification and quantification of 1-carboxysalsolinol and salsolinol in biological samples by gas chromatography--mass spectrometry

1-Carboxysalsolinol was found to be present in rat striatum, human urine and caudate nucleus of post mortem human brain, according to capillary column gas chromatographic retention times and selected ion monitoring of the hexafluoropropionyl ester pentafluoropropyl derivative. Simultaneous quantification of 1-carboxysalsolinol and salsolinol was performed in biological samples using deuterium labelled internal standards. In human urine, the precision of the method was +/- 7.1% (coefficient of variation, n = 25) for 1-carboxysalsolinol at 15 pmol/ml and +/- 8.5% for salsolinol at 10 pmol/ml. According to enzymatic hydrolysis, 68% of 1-carboxysalsolinol was found as conjugates in urine, and the corresponding figure for salsolinol was 92%. In human caudate nucleus, the amounts of 1-carboxysalsolinol were found to be significantly greater in brains from alcoholics, who at autopsy had ethanol present in the blood, whereas alcoholics without blood ethanol levels at autopsy had significantly lower concentrations of salsolinol.