1997 MCBRYDE-MEDAL-AWARD-LECTURE - RADIO-FREQUENCY QUADRUPOLE ION GUIDES IN MODERN MASS-SPECTROMETRY

The role of RF quadrupoles in modern mass spectrometer and tandem mass spectrometer systems is described. A good deal of the success in the application of tandem quadrupole mass spectrometers and atmospheric pr essure ionization mass spectrometers is due to new applications of the RF quadrupole ion guide. Developments that led from the use of very o pen, ''transparent'' electrodes in a cryopumped system to the opposite extreme of well-confined RF quadrupoles that operate advantageously a t pressures of several mTorr are described. The ion containment proper ties of RF quadrupoles are remarkably insensitive to the accuracy of t he electrode positions. This has allowed the use of novel quadrupole d esigns in order to provide unique solutions to instrumentational and p hysical-chemical problems.