非手性-手性色谱-预测多反应监测法分析中药毛前胡的化学成分
摘要
<p id=C2>Ligustici Radix (Chinese name: maoqianhu) consists of the dried roots of <italic>Ligusticum brachylobum</italic> Franch., which is mainly distributed in the Yunnan and Sichuan provinces. This herbal medicine has been primarily used for the treatment of cough in traditional Chinese medicine. Ligustici Radix is rich in coumarin derivatives. Interestingly, enantiomers and diastereomers are widely used for these coumarins, thus posing a great challenge for in-depth chemical profile characterization. In the present study, a new analytical platform, achiral-chiral liquid chromatography-tandem mass spectrometry (achiral-chiral LC-MS/MS) was configured to profile the chemical composition of Ligustici Radix. Because achiral and chiral columns were serially coupled, especially enantiomers, both chemically and enantiomerically selective separations could be accomplished simultaneously. The newly configured achiral-chiral LC-MS/MS platform did not require any electronic valve; hence, it could overcome the drawbacks of heart-cutting achiral-chiral two-dimensional LC, i. e., sophisticated instrumentation and limited reproducibility due to the use of electronic valve(s) and the undesired retention time shift across different analytical runs. Some available candidates for chemically selective or enantiomerically selective separation were assayed; then, Capcell core RP-C<sub>18</sub> column that was packed with core-shell type particles, and AD-RH column embedding amylose coated particles were employed the achiral and the chiral columns, respectively. The narrow-bore core-shell RP-C<sub>18</sub> column served as the front tool to achieve efficient chemoselective separation of coumarin analogs, and enantioselective enantiomers were obtained by using a wide-bore AD-RH chiral column. The predictive multiple reaction monitoring (predictive MRM) mode allowed for the sensitive detection of potential components, and an enhanced product ion (EPI) scan, which was a unique function o