Table 3.

Performance characteristics (validation results) for the quantitative analysis of amino acids

	Amino acid	Accuracy (%)	Carry-over (%)	LOD (μM)	LOQ (μM)	Linearity (μM)	r2	Repeatability (CV %)	Reproducibility (CV %)	Uncertainty of measurement (CV %)
1	Tryptophan	101.7	0.00	0.0	0.0	0.0–250.0	0.999	2.7	3.5	7.0
2	Phenylalanine	98.0	0.03	0.0	0.0	0.0–250.0	0.998	2.3	3.9	7.8
3	Leucine	100.9	0.08	0.0	0.1	0.1–500.0	0.999	2.4	4.1	8.2
4	Isoleucine	108.2	0.03	0.1	0.3	0.3–250.0	0.998	2.5	5.3	10.6
5	Valine	93.8	0.04	0.1	0.4	0.4–500.0	0.994	6.0	5.9	11.8
6	Methionine	84.0	0.00	0.0	0.0	0.0–100.0	0.998	1.9	4.2	8.4
7	Proline	100.8	0.05	0.0	0.1	0.1–500.0	0.998	2.4	4.9	9.8
8	Tyrosine	100.6	0.12	0.0	0.1	0.1–250.0	0.998	3.8	4.0	8.0
9	Pipecolic acid	98.1	0.03	0.0	0.0	0.0–20.0	0.999	0.8	6.6	13.2
10	Taurine	93.0	0.15	0.0	0.0	0.0–250.0	0.993	2.5	4.7	9.4
11	Alanine	96.7	0.06	0.1	0.3	0.3–1000.0	0.999	1.9	3.5	7.0
12	Hydroxy-proline	98.8	0.00	0.0	0.0	0.0–50.0	0.997	3.0	16.7	33.4
13	Threonine	95.3	0.04	0.0	0.0	0.0–500.0	0.998	2.9	6.2	12.4
14	Glycine	97.3	0.03	0.0	0.1	0.1–1000.0	0.994	3.8	8.0	16.0
15	Glutamine	91.2	0.00	0.1	0.2	0.2–1000.0	0.996	1.8	5.2	10.4
16	Serine	84.6	0.33	0.0	0.1	0.1–500.0	0.994	4.8	5.4	10.8
17	Asparagine	78.8	0.00	0.0	0.0	0.0–200.0	0.995	3.0	6.2	13.2
18	Citrulline	94.6	0.02	0.0	0.0	0.0–100.0	0.998	4.0	5.3	10.6
19	Glutamic acid	114.2	0.00	0.0	0.1	0.1–250.0	0.998	3.4	4.4	8.8
20	Aspartic acid	121.8	0.74	0.0	0.0	0.0–100.0	0.993	6.9	10.8	21.6
21	Histidine	101.0	0.05	0.0	0.1	0.1–250.0	0.999	2.3	3.5	7.0
22	Arginine	108.6	0.09	0.0	0.1	0.1–250.0	0.998	1.7	4.6	9.2
23	Lysine	102.0	0.00	0.0	0.1	0.1–500.0	0.999	2.2	4.4	8.8
24	Ornithine	98.2	0.03	0.0	0.1	0.1–250.0	0.999	2.9	4.7	9.4

The r² of the calibration curve was the mean r² of the calibration curve measured at three independent days (day 1, 5, and 10)