Table 3.

Calibration curve linear range, the coefficient of determination (R²), accuracy, and precision for the UHPLC-MS/MS assay of six milk thistle flavonolignans

Analyte	Linear range (ng/mL)	R2	Theoretical	Intraday (n = 5)			Interday (n = 12)
				Measured	Accuracy	Precision	Measured	Accuracy	Precision
			QC (ng/mL)	QC (ng/mL)	RE (%)	CV (%)	QC (ng/mL)	RE (%)	CV (%)
Silychristin	1.2–1024	0.9999	1.2	1.23	2.6	9.9	1.19	0.743	10.4
			5	4.91	1.75	6.78	5.04	0.875	8.23
			50	50.6	1.28	5.6	50.2	0.37	7.8
			1000	1022	2.2	2.48	1029	2.91	4.79
Silydianin	1.2–1024	0.9968	1.2	1.16	3.28	7.56	1.09	8.96	10.5
			5	5.03	0.54	2.05	4.97	0.577	5.46
			50	52.5	4.98	4.99	53.5	7.04	8.49
			1000	1010	0.962	2.74	1005	0.481	5.82
Silybin A	0.4–1024	0.9995	0.4	0.439	9.75	10.1	0.424	6.08	12.4
			5	5.06	1.14	3.51	5.29	5.83	5.05
			50	55.7	11.5	3.8	55.9	11.9	6.21
			1000	993	0.724	3.23	955	4.51	4.16
Silybin B	0.4–1024	0.9995	0.4	0.39	2.55	8.35	0.402	0.396	7.23
			5	5.04	0.824	5.22	5.03	0.662	6.25
			50	53.3	6.52	3.69	53.5	7	5.28
			1000	1023	2.34	3.14	980	1.97	7.03
Isosilybin A	0.4–1024	0.9999	0.4	0.39	2.55	8.72	0.398	0.396	14.6
			5	5.74	14.9	8.17	5.63	12.6	8
			50	56	12.1	6.05	57.3	14.5	6.77
			1000	1004	0.36	2.36	1025	2.51	3.45
Isosilybin B	0.4–1024	0.9998	0.4	0.395	1.2	8.58	0.402	0.521	8.89
			5	5.55	11	4.54	5.58	11.6	6.18
			50	53.9	7.78	5.79	56.3	12.7	5.83
			1000	1004	0.364	1.78	1005	0.457	3.31