What does a resolving power of 2,000 mean?
In its simplest form it means one can distinguish the peak at mass 2,000 from a peak at mass 2,001. There are more formal definitions of resolution which is M/Dm where M is the mass where the resolution is measured and delta m is the mass difference between two peaks of equal magnitude in which the valley between the peaks is 10%. The mass resolving power is defined for a single peak in which Dm is the full width of the peak at 50% of the height of the peak (i.e., the full width at half maximum (FWHM)). One advantage of the 50% definition is that then the definition of resolving power is the same as resolution (i.e., two peaks separated by one linewidth are barely resolved). For a discussion of resolution, resolving power, mass accuracy and mass precision see Marshall, A.G., Hendrickson, C. L., and Shi, S., D.-H., Anal. Chem., 2002, 74, 252A-259A.
