Table 3.

The intra- and inter-day precisions of four tanshinones in QC samples at three concentration levels (n = 6 replicates per day).

Analytes	Spiked Conc. (ng/mL)	Intra-Day		Inter-Day
		Measured Conc. (ng/mL)	RSD (%)	Measured Conc. (ng/mL)	RSD (%)
Tanshinone IIA	4.32	4.07 ± 0.07	1.75	4.09 ± 0.14	3.49
	21.6	19.14 ± 0.57	3.00	19.57 ± 0.67	3.40
	108	90.75 ± 1.27	1.41	91.95 ± 4.32	4.70
Cryptotanshinone	4.44	3.89 ± 0.23	6.01	3.93 ± 0.31	7.80
	22.2	19.93 ± 1.17	5.87	20.52 ± 1.17	5.69
	111	89.45 ± 2.03	2.20	94.20 ± 1.15	3.35
Dihydrotanshinone I	4.56	4.23 ± 0.30	7.19	4.22 ± 0.25	5.93
	22.8	20.82 ± 0.44	2.12	20.91 ± 1.14	5.46
	114	99.7 ± 4.37	4.38	97.8 ± 3.72	3.80
Tanshinone I	4.28	4.01 ± 0.20	4.92	4.00 ± 0.18	4.63
	21.4	19.87 ± 0.75	3.78	19.82 ± 0.85	4.29
	107	94.88 ± 3.77	3.98	97.57 ± 3.94	4.03