Rapid Analysis of 18 Flavonoids in Tea by Ultrahigh-Performance Liquid Chromatography Coupled with Quadrupole-Time of Flight Mass Spectrometry

Table 2

Linear relationships, LOD, LOQ, intraday, and interday precision of the 18 flavonoids.

Compound name	Linear equation	Linear range (ng/mL)	R^2	LOD (ppm)	LOQ (ppm)	Intraday precision (%)		Interday precision (%)
						0.2 (ppm)	2.0 (ppm)	0.2 (ppm)	2.0 (ppm)
Quercitrin	Y = 937.93572X − 60.94538	2.0–200	0.999	0.020	0.040	6.33	2.35	5.98	4.33
Myricetin	Y = 5573.98039X − 5141.38132	0.50–200	0.999	0.0040	0.010	2.65	4.10	4.18	5.33
Isoliquiritigenin	Y = 3.29233e4 − 684.58458	0.10–200	0.999	0.0010	0.0020	2.11	4.16	4.21	3.99
Silymarin	Y = 1303.67649X + 772.68571	0.50–200	0.999	0.0040	0.010	1.75	5.29	1.32	6.22
Isovitexin	Y = 7058.63154 − 6954.63317	0.50–200	0.999	0.0040	0.010	2.03	3.18	3.56	4.00
Vitexin	Y = 5907.43785 − 5540.04408	0.50–200	0.999	0.0040	0.010	4.56	1.69	4.95	3.26
Afzelin	Y = 933.85478X + 306.46076	2.0–200	0.999	0.020	0.040	7.21	6.98	6.98	5.93
Luteoloside	Y = 4256.71850X − 2641.93243	0.50–200	0.999	0.0040	0.010	3.26	4.19	4.15	3.29
Trilobatin	Y = 4758.23582X − 442.95230	2.0–200	0.999	0.020	0.040	2.41	3.25	3.66	5.87
Schaftoside	Y = 2857.85348X − 2820.37177	0.50–200	0.999	0.0040	0.010	8.32	4.33	9.29	5.12
Rutinum	Y = 614.44087X − 566.07374	5.0–200	0.999	0.040	0.10	0.141	1.98	2.65	6.59
Baimaside	Y = 337.15349 − 205.47768	2.0–200	0.999	0.020	0.040	1.89	6.59	3.26	4.19
Tiliroside	Y = 2058.79076X − 1139.28568	2.0–200	0.999	0.020	0.040	6.12	7.11	4.21	8.77
Camellianin A	Y = 328.76344X − 235.67547	2.0–200	0.999	0.020	0.040	4.50	4.32	5.00	6.31
Kaempferol	Y = 6203.83219X − 311.96940	1.0–200	0.999	0.010	0.020	6.22	4.88	7.19	5.09
Luteolin	Y = 6937.99180X − 180.55061	1.0–200	0.999	0.010	0.020	1.25	3.21	5.36	4.08
Quercetin	Y = 4111.83509X + 44.50690	1.0–200	0.998	0.010	0.020	2.97	1.78	6.23	5.19
Plantagoside	Y = 787.08819X + 1.18151	1.0–200	0.999	0.010	0.020	7.11	5.82	7.08	8.17