Gaseous ions and chemical mass spectrometry

Abstract

The intrinsic chemical reactivities of ions can be monitored in the gas phase using mass spectrometers that are coupled to appropriate ion sources and reaction cells. Here the author surveys his own experiences over the past 40 years as an ion chemist. He used flow-tube techniques for room temperature measurements of the intrinsic chemical reactivities of a large variety of positive and negative ions, including bare atomic ions, ions found in solution, biological ions, carbonaceous ions, and interstellar, cometary, and ionospheric ions. Progress in the measurement of chemical reactions of these ions with flow-tube mass spectrometry in the author’s laboratory was been driven largely by developments in techniques of ion injection into the flow tube and of ion production (e.g., by electron impact, plasma ionization, and electrospray ionization). Chemical topics that are covered include: acid-base and nucleophilic displacement reactions that have bridged the gap between the gas phase and solution; interstellar ions and their role in molecular synthesis such as the synthesis of amino acids; the chemistry of fullerene cations as a function of charge state; fundamentals and applications of the chemistry of atomic cations with an emphasis on transition metal and lanthanide cations; atomic metal-ion catalysis; and chemical reactions of singly and multiply charged biological anions and cations in the gas phase.Key words: ions, mass spectrometry, kinetics, ion chemistry.