RESUMEN
Object To develop a capillary GC-MS analytical method for identification and deter- mination of ginkgolide A, B, C and bilobalide (GA, GB, GC and BB) in Ginkgo biloba L. leaves. Methods The leave samples were extracted in ultrasonic bath with ethanol-water (20∶80). The extract was purified by liquid-liquid extraction with ethyl acetate followed by solid-phase extraction on a column mixed with acid Al 2O 3, active carbon and celite. The terpenes were trimethylsilylated by BSTFA (with 1% TMCS) for 60 min at 100 ℃ and determined by GC-MS with HP-5 MS capillary column in the selected-ion monitoring mode. The intense fragment ions were chosen as monitoring ions for quantitative analysis. Cholesterol was used as an internal standard. Column temperature gradient: initial temperature 180 ℃, maintained 1 min, and then increased at 20 ℃/min to 260 ℃, and finally at 2 ℃/min up to 300 ℃, maintained 2 min. Results The retention times of GA, GB, GC and BB were 13.7,14.3,15.3 and 6.8 min, the major fragmentation ions (monitoring) were at m/z 537, 625, 713 and 455 (299), the average recoveries of GA, GB, GC and BB were 102.0%, 99.4%, 96.0%, 96.3%, RSD were 0.54%, 2.40%, 1.98% and 2.43%, respectively. Conclusion This method is repeatable, specific, accurate and easy to operate. It is adoptable for quality and quantity analysis of terpene lactones from G. biloba leaves.