Evaluation of major historical ICR cell designs using electric field simulations

Abstract

In Fourier-transform ion cyclotron resonance mass spectrometry, ions are detected by measuring image current induced in the detecting electrodes by trapped ions rotating in a magnetic field at their cyclotron frequencies. The ion trap used for this purpose is called the Penning trap. It can have various configurations of electrodes that are used to create a trapping electric field, to excite cyclotron motion, and to detect the induced signal. The evolution of this type of mass spectrometry is mainly driven by progress in the technology of superconducting magnets and in the constantly improved design of the ion cyclotron resonance (ICR) measuring cell. In this review, we focus on ICR cell designs. We consider that the driving forces of this evolution are the desire to increase resolution, mass accuracy and dynamic range, as well as to adapt new methods for creating and trapping ions.

How to Increase Further the Resolving Power of the Ultrahigh Magnetic Field FT ICR Instruments? The New Concept of the FT ICR Cell–the Open Dynamically Harmonized Cell as a Part of the Vacuum System Wall

“…This provides an ideal phasing of cyclotronically excited ions of single- m / q ion clouds in the entire cell volume. In nonharmonized FT ICR cells, the mass resolving power is decreased because of the disintegration of the clouds of moving ions by destroying their rotational coherency . FT ICR instruments with a harmonized cell show a mass resolving power of more than 10 million at m / q = 1000 at relatively small magnetic fields like 7 T in the dipolar detection mode, which cannot be achieved in any other type of modern mass spectrometers.…”

Generalization of an Open Dynamically Harmonized Cell for Ultrahigh FT ICR Resolution

“…The resolving power in FT ICR MS is proportional to the time of coherent ion motion. To estimate this time the following procedure was used: 9 The time of coherent ion motion t ≃ 1/Δω, where Δω is the difference between the maximum and minimum rotation (cyclotron) frequencies in the area of ion localization. Using eq 10 for the area of rotating ion localization 0.5R < r < 0.7R, |z| < 0.5z 0 we performed a numerical search for the optimal k v as a function of k g for the best time of coherent ion rotation.…”

Fine Structure in Isotopic Peak Distributions Measured Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: A Comparison between an Infinity ICR Cell and a Dynamically Harmonized ICR Cell

“…2 Main atoms of organic compounds include carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus, etc. Among them, isotopes such as 12 C, 1 H, 16 O, and 14 N are referred to as the main isotopes. They have approximately 99% or even higher abundance, and 32 S has around 95% abundance.…”

“…Although not obvious at first glance, the DHC is also much simpler to tune for high performance. The details of the cell geometry designs can be found in a previous study …”

“…The details of the cell geometry designs can be found in a previous study. 12 In this study, two FTICR MS instruments were applied to investigate the effects of different magnetic fields and the different ICR cell designs on RP and mass accuracy. In addition to the DHC, the 15 T FT-ICR MS is also equipped with 2ω detection.…”