Validation of LC–MS/MS methods for quantitative analysis of kynurenine pathway metabolites in human plasma and cerebrospinal fluid: supplementary materials

Background: Dysregulation of the kynurenine metabolic pathway has been reported in several
neurological conditions. Methods & results: Sensitive and selective LC–MS/MS methods have been
validated for six kynurenine pathway metabolites in human cerebrospinal fluid and plasma. For each
matrix, we validated three methods – one for the simultaneous determination of kynurenine, kynurenic
acid, anthranilic acid and 3-hydroxy-kynurenine (four-analyte assay), one for quinolinic acid and one for
tryptophan – using stable-isotopically labeled internal standards. The dynamic range and quantitation
limits were based on endogenous concentrations for each analyte. Conclusion: The use of validated
methods for kynurenine pathway metabolites in human cerebrospinal fluid and plasma will provide
definitive information in neurological diseases.