Table 2.

Calibration curves, correlation coefficients, linear ranges, and LLOQ of the 13 analytes.

Compound	Regression equation	Linearity (r)	Linear range (ng/mL)
Chrysophanol	Y = 0.0828X + 0.00155	0.9995	1–729
Emodin	Y = 0.907X + 0.0512	0.9993	0.1–72.9
Aloe-emodin	Y = 0.0652X + 0.00257	0.9994	0.1–72.9
Rhein	Y = 0.465X + 0.119	0.9965	0.5–364.5
Physcion	Y = 0.0253X + 0.0016	0.9948	0.5–364.5
Questin	Y = 1.14X + 0.00681	0.9967	0.1–72.9
Citreorosein	Y = 0.102X + 0.00161	0.9998	0.1–72.9
Questinol	Y = 0.636X + 0.00179	0.9996	0.1–72.9
TSG	Y = 0.1X + 0.0259	0.9969	0.3–218.7
TG	Y = 0.592X + 0.00443	0.9993	0.1–72.9
CG	Y = 0.138X + 0.00767	0.9995	0.1–72.9
EG	Y = 0.54X + 0.0193	0.9991	0.1–72.9
PG	Y = 0.0576X + 0.00158	0.9995	0.1–72.9