Figure 2.

Representative chromatographic separation of a standard mixture of TRP-related metabolites containing an indole structure at a concentration 2 µg/mL, except for the internal standards: Tryptophan D₅, 0.4 µg/mL; 5-F Tryptamine 20 ng/mL; Melatonin OCD₃, 22 ng/mL. A. 5-OH Tryptamine, B. 3-OH Kynurenine, C. 5-OH Tryptophan, D. Kynurenine, E. Tryptamine, F. 5-OCH3 Tryptamine, G. Tryptophan D₅, H. Tryptophan, I. 3-OH Anthranilic acid, L. 5-F Tryptamine, M. N-Ac-5-OH Tryptamine, O. Anthranilic acid, P. Tryptophan ethyl ester, Q. Melatonin, R. Melatonin OCD₃, S. N-Ac Tryptamine.