Simultaneous Determination of Four Ingredients in Plantago Depressa by Single Marker

Table 9

Influence of different chromatographic columns and instruments on relative retention time.

Chromatographic instruments	Chromatographic columns	Relative retention time
		Protocatechuic acid	Catechin	Luteolin
Agilent 1260	Agilent ZORBAX SB-C18	0.3308	0.5017	1.049
	Phenomenex C18	0.3342	0.5128	1.0609
	Agilent TC-C18	0.3285	0.4996	1.0428
Shimadzu LC-2030	Agilent ZORBAX SB-C18	0.3317	0.5027	1.0634
	Phenomenex C18	0.3342	0.5101	1.0572
	Agilent TC-C18	0.3215	0.4988	1.0373
Mean		0.3302	0.5043	1.0518
RSD/%		1.44	1.15	0.99