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Quad ru pole

Fig. 1.17 The quadrupole mass analyzer is formed by four circular or hyperbolic rods placed in parallel. F Quadrupolar potential.

Quad ru pole

Fig. 1.17 The quadrupole mass analyzer is formed by four circular or hyperbolic rods placed in parallel. F Quadrupolar potential.

the RF voltage is maintained, the ions remain focused with no mass selectivity. Therefore, RF quadrupoles are ideal as ion guides or as a collision cell. Typically, quadrupole mass analyzers operate at unit mass resolution (FWHM 0.6-0.7 m/z units). There is a strong relation between resolution and transmission. In general higher mass resolution results in a decrease of transmission, but mass resolution corresponding to peak width of 0.1 m/z units without significant loss in sensitivity have also been reported. The mass range of quadrupoles is typically between m/z 5 and m/z 4000. Most common ionization sources are available on quadrupole instruments, including EI, ESI, APCI, APPI and MALDI.

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