Real-time monitoring of low-mass ions by applying quadrupolar excitation to remeasurement in Fourier transform ion cyclotron resonance mass spectrometry

• Published in: Journal of mass spectrometry. Vol. 35; no. 10; pp. 1191 - 1196
• Main Authors: Schmidt, Eric G., Richard Arkin, C., Laude, D. A.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.10.2000; Wiley
• Subjects: Analytical chemistry; Chemistry; Exact sciences and technology; Fourier transform ion cyclotron resonance; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; ion motion; Mass spectrometers and related techniques; Mass spectrometry; Organic chemistry; Physics; quadrupolar excitation; reaction profile; Reactivity and mechanisms; remeasurement; Spectrometric and optical methods; Ion molecule reaction; Fourier transformation; Efficiency; Benzene; Toluene; Spectral band profile; Ion cyclotron resonance spectrometry; Mass spectrometry; Quadrupole spectrometer; Signal to noise ratio
• ISSN: 1076-5174; 1096-9888
• DOI: 10.1002/1096-9888(200010)35:10<1191::AID-JMS47>3.0.CO;2-D

In the first application of quadrupolar excitation (QE) to the remeasurement of small ions, a remeasurement efficiency for benzene ions of 95% was achieved. The remeasurement experiment was optimized for excitation radius, static helium collisional cooling gas pressure and quadrupolar excitation amplitude. During initial studies conducted with benzene, it was found that maintaining an ion excitation that utilizes 12% of the full cell radius minimizes the effects of the non‐quadrupolar potential in a small cell. Optimization of the benzene remeasurement experiment permits the real‐time monitoring of an ion–molecule reaction, specifically the broadband QE remeasurement of the self‐chemical ionization of toluene. A single population of the benzyl precursor ion is monitored for over 100 s as it reacts to produce xylyl ion. More than 30 min would be required to acquire the same quantity of data by the conventional methods in which a new ion population must be generated for each reaction time studied; this results in a 90% decrease in the amount of time required to generate an ion–molecule reaction profile. This work demonstrates the first use of broadband QE remeasurement as a method for monitoring an entire low‐mass, gas‐phase ion–molecule reaction from a single population of ions. Copyright © 2000 John Wiley & Sons, Ltd.