Table 3.

Intraday and interday, precision, and accuracy for the determination of four constituents from the standard samples.

Nominal concentration (ng/mL)	Intraday			Interday
	Observed concentration (ng/mL)	Precision (%)	Accuracy (%)	Observed concentration (ng/mL)	Precision (%)	Accuracy (%)
Saikosaponin A
25	24.26 ± 3.33	13.74	−2.98	24.66 ± 1.74	7.04	−1.37
50	48.13 ± 3.25	6.75	−3.73	48.07 ± 2.47	5.14	−3.87
250	252.40 ± 3.24	1.28	0.96	248.14 ± 4.81	1.94	−0.74
500	497.80 ± 13.28	2.67	−0.44	509.28 ± 11.49	2.26	1.86
1000	1000.13 ± 6.46	0.65	0.01	995.71 ± 5.59	0.56	−0.43
Saikosaponin D
50	44.74 ± 3.88	8.67	−10.51	48.64 ± 2.73	5.60	−2.72
100	98.28 ± 5.57	5.67	−1.72	101.92 ± 4.71	4.62	1.92
250	258.05 ± 6.92	2.68	3.22	247.21 ± 5.25	2.12	−1.11
500	503.66 ± 11.20	2.22	0.73	505.82 ± 3.69	0.73	1.16
1000	996.29 ± 5.47	0.55	−0.37	997.57 ± 2.07	0.21	−0.24
Ferulic acid
50	42.54 ± 1.28	3.02	−14.93	48.54 ± 5.31	10.93	−2.92
100	100.01 ± 3.38	3.38	0.01	100.95 ± 4.85	4.80	0.95
250	265.09 ± 3.05	1.15	6.04	249.88 ± 10.51	4.21	−0.05
500	493.81 ± 1.86	0.38	−1.24	500.51 ± 12.88	2.57	0.10
1000	999.35 ± 1.12	0.11	−0.06	999.43 ± 6.03	0.60	−0.06
Paeoniflorin
50	45.52 ± 2.52	5.53	−8.96	47.88 ± 4.17	8.70	−4.25
100	96.55 ± 4.02	4.16	−3.45	101.20 ± 5.53	5.47	1.20
250	261.12 ± 4.89	1.87	4.45	248.78 ± 3.88	1.56	−0.49
500	501.96 ± 4.52	0.90	0.39	503.40 ± 17.55	3.49	0.68
1000	996.61 ± 2.52	0.25	−0.34	998.17 ± 8.86	0.89	−0.18

Notes: data are expressed as mean ± standard deviation (n = 6).

Precision: RSD (%) = [standard deviation/C _obs] × 100.

Accuracy: bias (%) = [(C _obs − C _nom⁡)/C _nom⁡] × 100.

Abbreviation: RSD: relative standard deviation.