title: Boosting Sensitivity in Liquid Chromatography-Fourier Transform Ion Cyclotron Resonance-Tandem Mass Spectrometry for Product Ion Analysis of Monoterpene Indole Alkaloids.
abstract: In metabolomics, the analysis of product ions in tandem mass spectrometry (MS/MS) is noteworthy to chemically assign structural information. However, the development of relevant analytical methods are less advanced. Here, we developed a method to boost sensitivity in liquid chromatography-Fourier transform ion cyclotron resonance-tandem mass spectrometry analysis (MS/MS boost analysis). To verify the MS/MS boost analysis, both quercetin and uniformly labeled (13)C quercetin were analyzed, revealing that the origin of the product ions is not the instrument, but the analyzed compounds resulting in sensitive product ions. Next, we applied this method to the analysis of monoterpene indole alkaloids (MIAs). The comparative analyses of MIAs having indole basic skeleton (ajmalicine, catharanthine, hirsuteine, and hirsutine) and oxindole skeleton (formosanine, isoformosanine, pteropodine, isopteropodine, rhynchophylline, isorhynchophylline, and mitraphylline) identified 86 and 73 common monoisotopic ions, respectively. The comparative analyses of the three pairs of stereoisomers showed more than 170 common monoisotopic ions in each pair. This method was also applied to the targeted analysis of MIAs in Catharanthus roseus and Uncaria rhynchophylla to profile indole and oxindole compounds using the product ions. This analysis is suitable for chemically assigning features of the metabolite groups, which contributes to targeted metabolome analysis.
authors.affiliation: RIKEN Center for Sustainable Resource Science Yokohama, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Nakabayashi
authors.affiliation: RIKEN Center for Sustainable Resource Science Yokohama, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsugawa
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University Chiba, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Kitajima
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University Chiba, Japan.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Takayama
authors.affiliation: RIKEN Center for Sustainable Resource ScienceYokohama, Japan; Graduate School of Pharmaceutical Sciences, Chiba UniversityChiba, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Saito
keywords: MIAtargeted analysis; liquid chromatography–Fourier transform ion cyclotron resonance–tandem mass spectrometry; metabolomics; monoterpene indole alkaloid (MIA); specialized metabolite; tandem mass spectrometry