Fragmentation study of tryptophan-derived metabolites induced by electrospray ionization mass spectrometry for highly sensitive analysis. Issue 7 (23rd February 2021)

• Record Type: Journal Article
• Authors: Asakawa, Daiki; Mizuno, Hajime; Sugiyama, Eiji; Todoroki, Kenichiro
• Is Part Of: Analyst. Volume 146:Issue 7(2021)
• Page Start: 2292
• Page End: 2300
• Publication Date: 2021-02-23
• Subjects: Chemistry, Analytic -- Periodicals; 543
• DOI: 10.1039/d0an02069a
• Languages: English
• ISSNs: 0003-2654

Abstract

Abstract : ESI of tryptophan-derived metabolites produced an intense signal of fragment ion with a spiro[cyclopropane-indolium] backbone. The use of corresponding fragment ions for the precursor of MRM transitions could improve the detection limit. Abstract : Liquid chromatography–tandem mass spectrometry (LC–MS/MS) is interfaced with electrospray ionization (ESI), which generally produces intact gas-phase ions of biomolecules. However, ESI induces the fragmentation of tryptophan-derived metabolites, which are known to act as neurotransmitters and psychoactive drugs. Tryptophan-derived metabolites undergo N–Cα bond dissociation during ESI, producing a fragment ion with a spiro[cyclopropane-indolium] backbone. Fragmentation is suppressed by the presence of an α-carboxyl group and the modification of amino groups. In particular, tryptamine and serotonin, which lack such functional groups, produce more intense fragment-ion signals than protonated molecules. The multiple reaction monitoring (MRM)-based quantitative analysis of tryptamine and serotonin used the fragment ions produced from in-source collision-induced dissociation as the precursor ions, which improved the signal-to-noise ratio of the resulting spectra. The present method allows for the quantitative analysis of tryptamine and serotonin with high sensitivity.