Enhanced accumulated trapping efficiency using an auxiliary trapping electrode in an external source Fourier transform ion cyclotron resonance mass spectrometer

Abstract

A scheme for the enhanced accumulation of ions injected into the trapped ion cell of a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer from an external electrospray ionization source is described. This method utilizes an auxiliary electrode positioned outside the trapped ion cell which increases the effective collisional path length for ions traversing the trapped ion cell. A comparison made between pressure-assisted accumulated trapping in a symmetric trapping well, an asymmetric trapping well, and a symmetric trapping well with that for the addition of an auxiliary electrode indicates that trapping efficiency can be significantly improved when an auxiliary electrode trapping configuration is utilized.