Resolution and its Experimental Determination

In principle, resolution is always determined from the peak width of some signal at a certain relative height and therefore, any peak can serve this purpose. As the exact determination of a peak width is not always easy to perform, certain doublets of known Am are being used. 

The minimum resolution to separate CO from is 28/0.011 2500. The doublet from the pyridine molecular ion, CsHsN , m/z 79.0422, and from the first isotopic peak of the benzene molecular ion, CCsHe, tti/z 79.0503, necessitates R = 9750 to be separated. Finally, the doublet composed of the first isotopic ion of [M-CHs] from xylene, m/z 92.0581, and toluene molecular 

Note There is no need to use a more accurate value of m/z than nominal and likewise, there is no use of reporting R = 2522.52 exactly as obtained for the C0 /N2 pair. It is fully suffident to know that setting R = 3(XX) is sufficient for one specific task or that R = 10,0(X) is suitable for another. 

With magnetic sector instruments a resolving power of up to / = 10,(XX) can routinely be employed, even R = 15,(XX). In practice, those instruments are rarely adjusted to resolve beyond R = 10,(XX), e.g., only when interferences of ions of the same nominal m/z need to be excluded. With an instrument in perfect condition, it is possible to achieve higher resolving power typically they are specified to deliver about R 60,(XX) (on intensive peaks). 

---