The ‘infinity Cell’: A New Trapped‐ion Cell With Radiofrequency Covered Trapping Electrodes For Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

The excitation event in Fourier transform ion cyclotron resonance mass spectrometry is optimized in order to obtain more reliable relative signal intensities and enhance the ion-selection performance in multi-tandem mass spectrometric experiments. Standard trapped-ion cells suffer from the undesirable ejection of ions along the symmetry axis (z-axis) of the cell, which is oriented parallel to the magnetic field lines. This z-eiection effect is difficult to predict, and thus difficult to avoid, especially when complicated broad-band excitation schemes are applied to the ions. An improved trapped-ion cell design, referred to as the ‘Infinity Cell’, is discussed which eliminates z-ejection. The Infinity Cell concept is based on the finding that it is possible to model the electric excitation field of an infinitely long cell with a cell of finite dimensions. The virtual elimination of z-ejection effects is demonstrated in several suitable experiments by comparing the operation of the standard cell and the Infinity Cell.