The QuadrupoleMass Filter: Basic Operating Concepts Philip E. Miller' and M. Bonner Denton University of Arizona, Tucson, AZ 85721 Quadrupole mass analyzers are now widely used in many areas of chemical analvsis. Althoueh referred to as - nooularlv .. quadrupole mass spectrometers, the mass-resolving properties of such devices are reallv much more akin to those of a tunable variable handpass mass filter. Only ions within a narrow mass region (generally
