A Simple HPLC-MS/MS Method for Determination of Tryptophan, Kynurenine and Kynurenic Acid in Human Serum and its Potential for Monitoring Antidepressant Therapy.

The kynurenine pathway, in which tryptophan is metabolized to kynurenine and kynurenic acid, has been linked to depression. A rapid and highly reproducible liquid-chromatography-tandem mass spectrometry (LC-MS/MS) method were established for determining tryptophan, kynurenine and kynurenic acid in human serum. Biological samples were precipitated with methanol before separation on an Agilent Eclipse XDB-C18.

Elucidation of in vitro phase I metabolites of droperidol using UPLC-QTOF MS.

Droperidol, an antidopaminergic drug clinically used as an antiemetic and antipsychotic, has been reported to induce cardiac toxicity in patients. Due to the close relationship between drug metabolism and efficiency and toxicity, the present study aims to investigate the phase I metabolites using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. The NADPH-supplemented phase I incubation system was used to elucidate the in vitro phase I metabolites.