Cai Min, Liu Yi-Ming
Department of Chemistry, Jackson State University, 1400 Lynch St., Jackson, MS 39217, USA.
Rapid Commun Mass Spectrom. 2008 Dec;22(24):4171-7. doi: 10.1002/rcm.3847.
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.
索索林醇，1-甲基-6,7-二羟基-2,3,4,5-四氢异喹啉（SAL），是帕金森神经毒素N-甲基索索林醇（N-甲基-SAL）的前体。先前的研究表明，N-甲基-SAL的各个对映体具有不同的神经毒理学特性。在这项工作中，开发了一种采用电喷雾电离串联质谱（ESI-MS/MS）检测的手性高效液相色谱（HPLC）方法，用于定量（R/S）-SAL对映体。在β-环糊精键合硅胶柱上实现了对映体分离，并通过以正离子模式运行的ESI-MS/MS检测分离出的对映体。同时研究了SAL及其氘代类似物（即索索林醇-α,α,α,1-d(4)，SAL-d(4)）的ESI碰撞诱导解离（CID）质谱，以便阐明其碎裂途径。此外，在SAL的HPLC/MS/MS分析中使用SAL-d(4)作为内标，显著提高了测定的准确性和可靠性。还展示了对食品样品如香蕉干片中存在的（R/S）-SAL对映体的测定。
