液相色谱-大气压化学电离质谱法分析人参中的人参皂甙

研究了用反相高效液相色谱-大气压化学电离质谱(HPLC/APCI-MS)分析人参皂甙的方法。液相色谱采用乙腈-水流动相进行梯度洗脱,质谱采用正负离子同时扫描并结合二级质谱进行定性,用选择反应离子模式(SRM)测定检测限。实验发现虽然人参皂甙是热不稳定物质,但在大气压化学电离质谱的高温汽化过程中仍能检测到很强的负离子分子离子峰,而且随着汽化温度的升高,人参皂甙的负离子分子离子峰的强度增加。该方法对人参皂甙Rb1和Rg1的检测限分别为1.2×10-13 g和3.0×10-14 g,并检测出白参中包括丙二酰人参皂甙在内的29种人参皂甙。该法灵敏度高,重复性好,结果准确,能有效地对药材提取物中的多种人参皂甙进行检测和结构分析。

Analysis of Ginsenosides in Ginseng by Liquid Chromatography-Atmospheric Pressure Chemical Ionization Mass Spectrometry

Analysis of ginsenosides using high performance liquid chromatography-tandem atmospheric pressure chemical ionization mass spectrometry (HPLC-APCI/MS) has been carried out. HPLC analysis was performed on a reversed-phase C18 column using mobile phase of acetonitrile and water mixture under gradient elution. Effects of evaporation temperature of APCI-MS on identification of ginsenosides were investigated. APCI/MS-MS spectra of [M-H]- were further resolved to identify the structures of ginsenosides. Detection limits of ginsenosides Rb, and Rg, were determined under selected reaction monitoring (SRM) mode. Ginsenosides in Panax ginseng (white ginseng) were assayed. Results show that although APCI is a high temperature evaporative process and ginsenosides are thermolabile compounds, abundant [M-H]- ions could be detected by using APCI-MS. The intensity of [M-H]- increased with the increase of evaporation temperature, which may due to more complete evaporation of elute solution at higher temperatures or due to the ionization mechanism of APCI. The detection limits of Rb1 and Rg1 were 1.2 x 10(-13) g and 3.0 x 10(-14) g, respectively. Twenty nine ginsenosides including malonyl-ginsenosides in Panax ginseng were identified. The method developed is sensitive, reproducible and accurate. Most ginsenosides in the extracts of ginseng could be effectively identified and analyzed for their structures.