Table 1.

Analytical performance data of the proposed method.

Analyte	Calibration curves	r 2	Linear range	LOD	LOQ	RSD (%, n = 3)
			μg mL−1	ng mL−1	ng mL−1	Peak area	Retention time
Aloe-emodin	y = 10.67x − 0.012	0.9997	0.012–1.200	4.1	12.1	2.35	0.38
Rhein	y = 9.14x − 0.020	0.9995	0.018–1.800	5.7	18.2	2.21	0.42
Emodin	y = 9.66x − 0.011	0.9996	0.015–1.500	5.1	15.2	1.84	0.29
Chrysophanol	y = 10.48x − 0.016	0.9993	0.012–1.200	3.9	12.0	2.48	0.26
Physcion	y = 9.55x − 0.012	0.9996	0.013–1.300	4.4	13.1	3.05	0.22