External phase shift ion ejection in fourier transform ion cyclotron resonance spectrometry

Abstract

By means of simple home-built add-on electronics, a highly specific ejection of ions in Fourier transform ion cyclotron resonance (FTICR) spectrometry by phase change swept frequency (notch ejection) is demonstrated. Typical applications are presented and it is shown that the phase shift ejection is superior to the usual swept frequency ejection with respect to resolution, ion retention as well as user friendliness. Complete ejection of N 2 + ions in the presence of C 2H 4 + ions (Δ m/ z = 0.025 u) is demonstrated. Unwanted excitation of ions is discussed.