Table 3.

Intra-day recovery, accuracy and assay precision for validation of the analytical method developed.

Analyte (conc.)	Spike level	†%Recovery	*Accuracy (% deviation)	Precision (% RSD)
AA (nM)	100	102 ± 6	3 ± 1	6
	501	94 ± 4	5 ± 4	4
	1002	104 ± 3	4 ± 3	3
PA (nM)	96	97 ± 5	5 ± 3	5
	561	103.3 ± 0.2	3.3 ± 0.2	0.2
	962	102.1 ± 0.9	2.1 ± 0.9	0.9
KA (nM)	50	114 ± 27	13 ± 7	24
	100	90 ± 5	6 ± 3	5
	1003	101 ± 3	2.8 ± 0.5	3
QA (nM)	197	110 ± 10	5 ± 4	9
	1077	106 ± 11	8 ± 6	11
	5385	98 ± 6	5 ± 3	6
TRP (μM)	71	92 ± 6	5 ± 3	7
	142	103 ± 2	3 ± 2	2
	282	104 ± 3	4 ± 3	3
KYN (μM)	4	114 ± 6	11 ± 4	5
	8	90.0 ± 0.9	8.7 ± 0.7	1
	16	98.3 ± 0.5	1.5 ± 0.5	0.5

^†The assay recovery for the validation was calculated as follows: spiked recovery= 100 × (measured concentration for spiked sample - the measured concentration for nonspiked sample)/spiked value;

measured concentration of spiked sample = mean basal concentration (X) + spiked conc;

measured concentration for nonspiked sample = mean basal concentration (X).

mean basal concentration is determined as an unknown concentration value obtained from the calibration curve shown in Fig. S7; spiked value = added standard concentration.

^*The assay accuracy (% deviation) = 100 × І(measured concentration for spiked sample - the theoretical concentration for spiked sample)І/ the theoretical concentration for the spiked sample.

Theoretical concentration for spiked sample = mean basal concentration + added standard concentration.