. 2020 Apr 9;9(4):305. doi: 10.3390/antiox9040305

Table 2.

Validation parameters of the QuEChERS-USAE/UHPLC-PDA methodology for the determination of polyphenols in fruits and vegetables.

No.	Analytes	Rt ^a (min)	λ_max ^b (nm)	Regression Equation	R ²	Mandel Test		LOD (µg/mL)	LOQ (µg/mL)	Concentration Level (µg/mL)	Precision (RSD%)		Trueness (Bias %)	Recovery ± σ (%)
No.	Analytes	Rt ^a (min)	λ_max ^b (nm)	Regression Equation	R ²	TV ^c	F (0.95; 1; N-3) ^d	LOD (µg/mL)	LOQ (µg/mL)	Concentration Level (µg/mL)	Intra-day (n = 6)	Inter-day (n = 18)	Trueness (Bias %)	Recovery ± σ (%)
1	Protocatechuic acid	2.825	259	7.6389x − 29.253	0.9972	1.98	18.5	0.10	0.30	5	19	20	−19	65 ± 4
										10	2	14	−2	77 ± 7
										25	14	10	−11	86 ± 2
2	(+)-Catechin	3.222	278	0.9936x − 5.1953	0.9892	1.79	18.5	0.20	0.60	5	20	20	20	77 ± 1
										10	18	17	15	68 ± 4
										15	16	15	2	97 ± 3
3	Gentisic acid	3.856	327	0.9141x + 0.2776	0.9996	1.93	18.5	0.04	0.12	5	20	18	7	86 ± 11
										10	12	20	1	102 ± 7
										25	11	6	7	109 ± 2
4	Vanillic acid	4.522	261	2.2658x − 1.562	0.9904	1.75	18.5	0.19	0.57	5	7	8	−14	78 ± 7
										10	10	15	−14	79 ± 7
										25	13	7	−11	106 ± 2
5	Syringaldehyde	5.322	308	2.2374x − 2.1762	0.9981	1.94	18.5	0.08	0.25	5	16	14	−18	72 ± 13
										10	15	17	−10	88 ± 4
										25	14	8	10	104 ± 5
6	p-Coumaric acid	5.688	309	4.75x − 2.2961	0.9891	1.23	18.5	0.20	0.61	5	10	14	−20	97 ± 4
										10	9	17	−3	87 ± 2
										25	13	8	0.5	112 ± 4
7	Ferulic acid	6.038	323	2.9341x − 0.991	0.9925	0.91	18.5	0.17	0.50	5	4	8	2	92 ± 9
										10	14	17	−4	75 ± 21
										25	9	9	−6	103 ± 7
8	m-Coumaric acid	6.503	278	4.4605x + 5.4055	0.9930	1.87	18.5	0.16	0.48	5	11	18	−1	69 ± 8
										10	11	16	−2	86 ± 11
										25	14	7	0.3	102 ± 5
9	o-Coumaric acid	7.473	276	4.0666x + 0.831	0.9963	0.49	18.5	0.12	0.35	5	18	20	−9	59 ± 1
										10	8	9	−6	80 ± 10
										25	13	11	−4	107 ± 4
10	Cinnamic acid	9.529	277	4.4086x + 0.0199	0.9984	1.71	18.5	0.08	0.23	5	20	20	−20	92 ± 8
										10	11	16	−0,2	89 ± 5
										25	13	9	6	102 ± 8
11	Quercetin	9.729	372	1.75x + 0.6423	0.9982	1.06	18.5	0.08	0.25	5	14	19	−9	78 ± 14
										10	13	16	−4	79 ± 7
										25	14	12	10	106 ± 8
12	Kaempferol	10.484	366	2.1524x + 1.2044	0.9972	0.99	18.5	0.10	0.31	5	19	20	−5	80 ± 3
										10	10	18	−2	80 ± 3
										25	14	13	−8	105 ± 8

^a Rt: retention time; ^b λ_max: maximum absorbance value obtained in PDA system detection; ^c TV: test value; ^d F (0.95; 1; N-3): Fisher/Snedecor F-distribution tabulated values for a 95% confidence.