Quantification of salsolinol enantiomers by stable isotope dilution liquid chromatography with tandem mass spectrometric detection.
Salsolinol, 1-methyl-6,7-dihydroxy-2,3,4,5-tetrahydroisoquinoline (SAL), is a precursor of a Parkinsonian neurotoxin, N-methysalsolinol (N-methyl-SAL). Previous studies have shown that individual enantiomers of N-methyl-SAL possess distinct neurotoxicological properties. In this work, a chiral high-performance liquid chromatography (HPLC) method with electrospray ionization tandem mass spectrometric (ESI-MS/MS) detection was developed for the quantification of (R/S)-SAL enantiomers. Enantioseparation was achieved on a beta-cyclodextrin-bonded silica gel column, and the resolved enantiomers were detected by ESI-MS/MS operated in positive ion mode. The ESI collision-induced dissociation (CID) mass spectrum of SAL was studied together with that of its deuterium-labeled analog (i.e. salsolinol-alpha,alpha,alpha,1-d(4), SAL-d(4)) so that the fragmentation pathways could be elucidated. Further, using SAL-d(4) as internal standard in HPLC/MS/MS analysis of SAL improved significantly assay accuracy and reliability. Determination of (R/S)-SAL enantiomers present in food samples such as dried banana chips was demonstrated.
Cai
Min
M
Department of Chemistry, Jackson State University, 1400 Lynch St., Jackson, MS 39217, USA.
Liu
Yi-Ming
YM
D002851:Chromatography, High Pressure Liquid; D003903:Deuterium / Q000032:analysis; D005506:Food Contamination / Q000032:analysis*; D007546:Isoquinolines / Q000032:analysis*; D028521:Musa / Q000737:chemistry; D015203:Reproducibility of Results; D012490:Salsoline Alkaloids / Q000633:toxicity; D012639:Seeds / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013237:Stereoisomerism; D053719:Tandem Mass Spectrometry / Q000379:methods*; D027843:Vitis / Q000737:chemistry
D007546:Isoquinolines; D012490:Salsoline Alkaloids; C036617:salsolinol; C032837:salsoline; D003903:Deuterium