The Mass Spectrometry society of Japan - The 68th Annual Conference on Mass Spectrometry, Japan
Japanese

Abstract

Table of contents

Timetable

Plenary Lectures

Award Lecture

Oral Sessions (Day1, Day2, Day3)

Poster Presentations (Day1, Day2, Day3)

Panel Discussion

Luncheon Seminars (Day1, Day2, Day3)

Corporate Program

Oral Sessions

Day 3, June 24（Fri.）　14:40-15:20　Room C (411 and 412)

3C-O2-1440　　PDF

Proton Transfer of Protonated Molecules Studied by Ion Mobility-Mass Spectrometry

(Tohoku Univ.)
oKeijiro Ohshimo, Ryosuke Sato, Yuya Takasaki, Fuminori Misaizu

Two mechanisms of proton transfer are well established; the Grotthuss mechanism (proton-relay) and the vehicle mechanism. Intramolecular proton transfer has been extensively studied in the gas phase to understand the proton transfer mechanism microscopically. However, only the Grotthuss mechanism was proposed so far for intramolecular proton transfer. Here we show the evidence for proton transfer via the vehicle mechanism in a gas-phase protonated molecule. Using ion mobility-mass spectrometry, we observed that a single NH3 molecule induces intramolecular proton transfer between two structural isomers with different protonation sites of protonated p-aminobenzoic acid (PABA; p–NH2C6H4COOH). In combination with theoretical calculations of the reaction pathway for the bimolecular reaction of PABA·H++NH3, it was concluded that intramolecular proton transfer to produce the O-protomer (protonated PABA at the C=O group) proceeds in the N-protomer (protonated PABA at the NH2 group) by NH3 coordination.