Author ORCID Identifier


Date of Award

Fall 12-12-2022

Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Dr. Gangli Wang


Tryptophan (TRP) is one of the nine essential amino acids metabolized through various metabolic pathways in the human body. The kynurenine pathway (KP) of TRP metabolism is known to be regulated differently in different disease conditions. The accurate measurement of the TRP metabolites and study of their regulation in biofluids under different disease conditions is of greaat importance. The work in this dissertation presents the development of repeatable and sensitive capillary electrochromatography (CEC) and liquid chromatography (LC) with tandem mass spectrometry (MS/MS) detction methods for quantitative analysis of tryptophan and its kynurenine pathway metabolites in human cerebrospinal fluid and plasma. The 4-VPBA was evaluated as a novel stationary phase and its applications in CEC-MS/MS separation and quantitative analysis of TRP and KYN in human plasma samples was deminstrated. The development of repeatable, selective, and highly sensitive LC-MS/MS method using reversed phase (C-8) for the simultaneous separation and quantitation of TRP and its eight metabolites in human cerebrospinal fluid (CSF) and plasma samples is reported. Using the developed reversed-phase separation method, the baseline separation of all nine target metabolites was achieved for the first time to our knowledge. The dynamic multiple reaction monitoring (MRM) feature of triple quadrupole MS was utilized to improve the selectivity and sensitivity of the developed multi-analyte method. Finally, this dissertation presents the correlations of TRP metabolites in two biofluids (CSF and plasma) and their regulations in neuroinflammation conditions.


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