Figure 5

Quantification of kynurenine and tryptophan in healthy control and SCLC patients using LC–MS/MS. (A) Stripped plasma blank showing no peaks for endogenous Kyn and Trp. (B) Chromatogram showing separation of Kyn, Trp and homatropine (HA) which is used as an internal standard (IS). (C) Representative plasma concentration of Kyn and (D) Trp in control and patient sample, respectively. (E) Kyn levels in the plasma samples of healthy control and SCLC patients. (F) Trp levels in the plasma samples of healthy control and SCLC patients. (G) Kyn/Trp ratio of healthy control and SCLC patients.