Determining the Levels of Four Phenylethanoid Glycosides and Five Triterpene Acids in Liuwei Dihuang Capsule Using Solid Phase Extraction with HPLC-UV

Table 2

Method validation parameters of the four phenylethanoid glycosides and five triterpenes.

Compound	Intraday precision (RSD%), n = 6	Interday precision (RSD%), n = 3	Regression equation Y = aX + b^a	Correlation coefficient (r)	Recovery ± SD^b (%)	LOD (μg/mL)	LOQ (μg/mL)
Purpureaside C	0.72	0.98	Y = 9.8161X + 0.8779	0.9999	93.7 ± 0.5	0.0044	0.0125
Jionoside A1	0.65	0.87	Y = 8.9245X + 2.5501	0.9998	94.2 ± 0.6	0.0031	0.0124
Acteoside	0.58	0.64	Y = 15.767X − 9.6178	0.9995	95.5 ± 1.2	0.0027	0.0081
Isoacteoside	0.82	1.02	Y = 13.012X − 4.3485	0.9996	93.3 ± 0.8	0.0028	0.0076
3-O-Acetyl-16α-hydroxytrametenolic acid	0.35	0.68	Y = 6.6677X − 0.5066	0.9998	91.8 ± 0.2	0.052	0.186
Dehydropachymic acid	0.62	1.05	Y = 6.2417X + 0.0102	0.9999	96.6 ± 0.3	0.073	0.205
Pachymic acid	0.84	1.08	Y = 6.4675X − 1.3874	0.9998	97.8 ± 1.5	0.136	0.418
Trametenolic acid	0.46	0.85	Y = 6.4439X − 0.4147	0.9996	95.2 ± 0.6	0.087	0.252
Dehydrotrametenolic acid	0.55	0.92	Y = 6.0755X + 1.626	0.9997	94.5 ± 1.2	0.064	0.198

^aY is the peak area while X is the concentration (μg/mL). ^bStandard deviation, n = 3.