Table 2. The regression equation, LOD and LOQ of the four standards using the optimized method for calibration.

Compounds	Regression equation	r2	Linear range (μg/mL)	LOD (μg/mL)	LOQ (μg/mL)
Gastrodin	y = 79899x - 1108.1	0.9999	8.89–44.48	0.024	0.081
Parishin E	y = 19656x - 12538	0.9915	6.08–60.80	0.143	0.475
Parishin B	y = 19656x - 12538	0.9981	34.50–138.00	0.104	0.345
Parishin	y = 315580x - 7052.4	0.9999	40.66–203.30	0.359	1.196

y, peak area; x, compound concentration (μg/mL); LOD = limit of detection, S/N = 3; LOQ = limit of quantitation, S/N = 10