Characteristics of a quadrupole mass filter in the separation mode of a few stability regions

The quadrupole mass filter can be operated in some stability regions. Such regions as zone II (7.57969 < q < 7.51361), zone III (21.303174 < q 21.288631) localized along the q axis, zone Π1 near the operation “tips” (3.23408, 3.16429) and (2.8153, 2.5212) and zone Π2 at the lower operation tip (6.381, 7.976) have been investigated. The operation areas of these zones are given in detail. Some characteristics of the quadrupole mass filter are discussed such as acceptance, resolution, transmission, field quality effects and coupling of the analysers of the tandem mass filter. The practical importance of zone Π1 is emphasized.