INTERFACE FOR A 4-SECTOR MASS-SPECTROMETER WITH A DUAL-PURPOSE COLLISION CELL - HIGH TRANSMISSION AT LOW TO INTERMEDIATE ENERGIES

A new interface system that consists of an ion decelerator, a floating collision cell-chemical ionization ion source, and an ion extractor w as designed and installed in the third field-free region of a four-sec tor tandem mass spectrometer. Important features include the use of cy lindrical deceleration lenses and an extraction lens assembly. This ne w design was found to provide enhancement of ion transmission at low t o intermediate ion kinetic energies (3 eV to 1 keV) compared with the standard collision cell design. Collision-induced dissociation experim ents from 3 eV to 10 keV and ion-molecule reactions of mass-selected i ons can be performed conveniently. A second, grounded, collision cell is located after the extraction lenses, which allows MS(4) experiments to be carried out via the normal linked (B/E) scan function in MS2. I ncorporation of chemical ionization capability into the electrically i solated collision cell makes it possible to carry out neutralization c hemical-reionization mass spectrometry.