. Author manuscript; available in PMC: 2013 Feb 15.

Published in final edited form as: Anal Biochem. 2011 Dec 28;421(2):573–581. doi: 10.1016/j.ab.2011.12.032

Table 1.

Detection of tryptophan and its metabolites by GC/MS/MS. See text for experimental details.

Metabolites	MW (amu)	Time segment	SRM transition Q1 → Q3 (m/z) /	Collision energy (V)	Rt (min)
Quinolinic acid	431.2	1	431.0 → 298.0	10	8.8
3-Hydroxykynurenine	794.3	2	630.0 → 219.0	10	12.3
L-Kynurenine	632.3	3	612.0 → 442.0	10	12.5
L-Tryptophan	628.3	3	608.2 → 351.0	20	12.5

[²H₃]Quinolinic acid	434.2	1	434.0 → 301.0	10	8.8
[²H₆]L-Kynurenine	638.3	3	618.0 → 447.0	10	12.5
[²H₅]L-Tryptophan	633.3	3	613.2 → 351.0	20	12.5

MW: Molecular weight of analytes and deuterated standards after derivatization; Rt: Retention time; Q1, Q3: Quadrupoles. “Time segment” refers to the acquisition time periods depicted in Fig. 3.