[Determination of five protopanaxadiol ginsenosides in ginseng by solid-phase extraction-ultra performance liquid...

A new method based on solid-phase extraction-ultraperformance liquid chromatography (SPE-UPLC) was developed for the determination of five protopanaxadiol ginsenosides in ginseng. The ginsenosides were extracted from ground ginseng samples using water-saturated n-butanol and purified on a hydrophilic solid-phase extraction column. Chromatographic separation was achieved on an ACQUITY UPLC BEH Shield RP18 column (100 mm×2.1 mm, 1.7 μm) by linear gradient elution using an acetonitrile/water mobile phase. Five protopanaxadiol ginsenosides were detected by a photodiode array detector, and they showed a strong positive linear correlation (r²>0.999) in the range of 5-500 μg/mL. In addition, the instrument precision ranged between 0.95% and 2.62% (n=6), with the sample stability between 0.90% and 2.15% (n=8) within 22 h. Intra- and inter-day repeatabilities were 5.35%-6.47% (n=6) and 5.56%-6.34% (n=8), respectively. Sample recoveries and the corresponding relative standard deviations (RSDs) were 87.16%-101.92% and 1.54%-4.01% (n=6), respectively. Hydrophilic chromatography materials were used in SPE, and the extract was directly loaded and purified without pretreatment. Besides, with the use of UPLC, the analysis time was greatly shortened. The developed method is simple and rapid, with high throughput, thus being suitable for the quantitative analysis of the five protopanaxadiol ginsenosides in ginsengs.