串联毛细管手性柱分离薄荷醇的8 种光学异构体

为分离和检测食品和药品中的薄荷醇旋光异构体,通过详细研究非手性毛细管柱和手性毛细管柱对8 种薄荷醇旋光异构体的分离效能,建立串联手性毛细管色谱柱分离、气相色谱-质谱法定量检测糖果食品和药品中8 种薄荷醇旋光异构体的方法。结果显示：无特殊选择性固定相的DB-5MS、DB-624、DB-ALC1、DB-INNOWAX毛细管柱均能实现D/L-薄荷醇、D/L-新薄荷醇、D/L-异薄荷醇、D/L-新异薄荷醇4 对对映异构体的分离,但不能实现其D型和L型旋光异构体的分离。结合CycloSil-B、BGB-175手性毛细管柱分离薄荷醇异构体的互补能力,采用CycloSil-B＋BGB-175串联手性毛细管柱,成功分离了8 种薄荷醇旋光异构体,色谱峰均达到分离要求,峰形尖锐对称,响应值和保留时间具有较好稳定性,分离条件下柱流失较小,对薄荷醇检测无明显影响。建立了糖果食品和药品中8 种薄荷醇旋光异构体的定量测定方法,方法的定量限为23.0～72.9 μg/L,加标回收率为86.0%～116.0%。该方法成功用于糖果食品和药品中薄荷醇旋光异构体的分离和检测,结果显示所有样品中检测到的薄荷醇均以L-薄荷醇为主,大部分样品中检测到微量的其他薄荷醇异构体,并可通过薄荷醇异构体构型组成对不同样品中薄荷醇类型进行区分。

Separation of Eight Optical Isomers of Menthol by Tandem Capillary Chiral Columns

Based on a detailed understanding of the separation efficiency of eight menthol optical isomers on different chiral and non-chiral capillary columns, a method for the quantitative determination of them was established using gas chromatography-mass spectrometry (GC-MS) after separation on tandem chiral capillary columns. The results showed that four enantiomeric pairs of menthol were separated on DB-5MS, DB-624, DB-ALC1 and DB-INNOWAX capillary columns with non-chiral stationary phase, but the D- and L-enantiomers failed to be separated from each other. The eight menthol optical isomers were successfully separated on tandem CycloSil-B and BGB-175 chiral capillary columns by virtue of the complementarity between them. Being sharp and symmetrical, the chromatographic peaks all met the requirements for separation. The response value and retention time had good stability, and the stationary phase loss was small during the separation process, causing no significant impact on menthol detection. The limit of quantification (LOQ) of the developed method was 23.0–72.9 μg/L, and the recoveries of the spiked analytes ranged from 86.0% to 116.0%. This method was successfully utilized for the separation and quantitative detection of menthol optical isomers in candy and drugs, indicating that the dominant form of menthol in the samples tested was L-menthol, and other menthol isomers were also detected at trace levels in most samples. In addition, menthol types in different samples were distinguished by menthol isomer configuration.