Novel linear ion trap mass analyzer built with triangular electrodes.

Abstract

A novel linear ion trap mass analyzer built with four triangular electrodes, the triangular-electrode linear ion trap (TeLIT), has been built and its performance has been characterized. The TeLIT has all the properties of a conventional LIT mass analyzer, performing ion trapping, mass analysis, and tandem mass spectrometry functions. The TeLIT was constructed with four identical triangular cross-section shaped electrodes and two planar electrodes. Unlike commercial LITs, which have very well-defined hyperbolic shaped electrodes, the TeLIT electrodes have a much simpler geometric structure and larger mechanical tolerances. The electric field distribution inside the IT region was simulated and there are more quadrupole field components and less higher order fields compared with those in other simplified ITs, such as cylindrical ion trap and rectilinear ion trap; hence, the instrument would potentially offer a relatively high mass resolution. In routine measurement, mass analysis with a resolving power of over 1500 at m/z = 609 Th was obtained. The TeLIT was shown to perform basic mass spectrometer functions such as mass-selected isolation, mass-selected ejection and collision-induced dissociation (CID) of ions comparable to other available LITs. Moreover, given the small size of the TeLIT and its simple structure and good analytical performance, further miniaturization and use as a portable mass spectrometer are envisaged.