Study for practical use of two chiral analyses of amphetamines by gas chromatography-mass spectrometry

点击翻译按钮获取中文摘要

Amphetamines possess respectively symmetric isomers (enantiomers). Usually, d-enantiomers are taken by stimulant abusers. L-enantiomers are rarely abused, but the compounds are possible to be detected in toxicological analysis. L-methamphetamine and l-amphetamine, because, are also main metabolites of a therapeutic drug, selegiline. It is important to distinguish the abused drugs with the therapeutic drugs in forensic toxicological analysis. We have been developing two methods for chiral analysis of amphetamines by gas chromatography-mass spectrometry (GC/MS). Those trial methods were successfully prepared, but the chromatographic performances were time-consuming. Therefore, we attempted to shorten the chromatographic periods on those methods. Method I : A sample solution was pH-adjusted at 12.6 then applied to a diatomaceous earth column and extracted with trifluoroacetylprolylation. The derivatized amphetamines were analyzed by GC/MS with a DB-5 narrow-bore column at a high-pressure for first chromatographic performance. Method II : A sample solution was placed in a headspace vial containing a heap of sodium chloride, alkalized (not strong) and added heptaflurobutyryl chloride. The vial was set onto an auto-sampler for solid-phase microextraction (SPME) for GC/MS analyzing in a chiral column Rt-betaDEXsm (0.25 mm i.d. x 30 m, film thickness 0.25 μm). In this case, amphetamines were detected as heptafluorobutyryl derivatives. In method I, distinguishable enantiomer peaks with very short periods were observed. In method II, the observed peaks were faster than conventional conditions. As regular chiral analysis, method I is superior to method II. Meanwhile, method II is useful for forensic toxicological analysis using putrefied or decomposed body materials.