Page 140 - An Introduction to Analytical Atomic Spectrometry - L. Ebdon
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ions are deflected (cf. polychromator used for optical spectrometry), thereby allowing truly
simultaneous mass analysis. Magnetic sector mass analysers are more expensive and less easy to
operate than quadrupoles, mainly because they require more stable operating environments. Magnetic
sectors cannot be scanned as rapidly as quadrupoles, although modern instruments are capable of
scanning 2-260 m /z in less than 1 s, and they are also capable of simultaneous operation for a limited
number of masses.
5.4.3 Resolution
The main advantage of a magnetic sector is the high degree of resolution obtainable. Resolution is
defined as
where R is resolution, M is mass (strictly m /z) and AM is peak width at 5% peak height. This is
concept is illustrated better in Fig. 5.7. The resolution
Figure 5.7
Definition of mass resolution, R.
