Thus, the answer to the question of “how much is enough mass resolving power” requires that one first specify S/ N ratio, dynamic range, digital resolution, mass-to-charge ratio, and (if available) isotopic fine structure.
Finally, the reliability of elemental composition assignment can be improved by resolution of isotopic fine structure. Mass accuracy depends on mass spectral signal-to-noise ratio and digital resolution. Mass resolving power also depends on mass-to-charge ratio. Ergo, minimum resolving power requires specification of maximum dynamic range, and is thus 10–100× higher than the conventional definition. Although mass resolution is conventionally defined as the closest distinguishable separation between two peaks of equal height and width, the required mass resolving power can be ∼10× higher for equal width peaks whose peak height ratio is 100 : 1. Accurate mass measurement requires the highest possible mass resolution, to ensure that only a single elemental composition contributes to the mass spectral peak in question.
