Table 1.

Summary of validation parameters.

Parameters	Caffeic acid	Quercetin	Apigenin	CAPE
Linearity range (μg/mL)	20–70	30–80	20–70	20–70
Regression equation	y = 5024x + 1464	y = 37,619x − 79,941	y = 70,037x − 1,377,000	y = 56,240x − 60,582
r2	0.998	0.999	0.999	0.998
Slope	5024	37,619	70,037	56,240
Intercept	1464	79,941	1,377,000	60,582
Retention time (min)	1.993 ± 0.125	3.153 ± 0.073	3.757 ± 0.138	5.804 ± 0.069
Theoretical plates	2795 ± 0.088	3496 ± 0.078	5202.8 ± 0.898	7359.5 ± 0.188
LOD (μg/mL)	2.413	1.649	1.752	2.499
LOQ (μg/mL)	7.312	4.997	5.309	7.572
Precision
Intra-day	≤ 2	≤ 2	≤ 2	≤ 2
Inter-day	≤ 2	≤ 2	≤ 2	≤ 2
Accuracy (%)	97.410–99.520	98.920–99.820	97.750–99.330	98.350–99.720
Robustness	≤ 2	≤ 2	≤ 2	≤ 2

r² – square of correlation coefficient, LOD – limit of detection, LOQ – limit of quantitation, μg/mL – microgram per milliliter, % RSD – percent relative standard deviation.