Table 1. Figures of merit obtained from the calibration curves used for quantitation.

Analyte	Calibration range	Retention Time (min)a	Concentration range (LLOQ – ULOQ)	R2, b	LOD (nM)	LOQ (nM)
p-Tyr	0.4 – 200 μM	1.452±0.003	0.44 – 220 μM	0.996	39.0	129.9
m-Tyr	16 – 250 nM	1.889±0.012	17 – 275 nM	0.996	1.2	3.9
o-Tyr	16 – 1000 nM	2.733±0.009	17 – 1100 nM	0.998	2.8	9.5
Phe	0.2 – 200 μM	3.100±0.003	0.22 – 220 μM	0.9991	14.4	48.0
3NO2-Tyr	16 – 1000 nM	3.415±0.004	17 – 1100 nM	0.995	4.2	14.0
3Cl-Tyr	7 – 2000 nM	3.211±0.008	8 – 2200 nM	0.997	0.9	3.0
2dG	7 – 1000 nM	2.51±0.02	8 – 1100 nM	0.996	0.7	2.5
8OHdG	2 – 250 nM	3.263±0.010	2.2 – 275 nM	0.993	0.2	0.6

^a: mean values ± standard deviation;

^b: Regression coefficient for the linear regression curves calculated using (Peak Area Metabolite)/(Peak Area of the Internal standard).as response, and ((Metabolite)/(Internal standard)) as independent variable. Internal standard: Phe-D₅