6/15/2023 0 Comments Spectrometer resolution calculator![]() Recent examples include resolution and identification of tens of thousands of monoisotopic elemental compositions from a single mass spectrum of petroleum crude oil 2) and unit mass resolution of an intact 147 kDa antibody. Our treatment focuses on Fourier transform ion cyclotron resonance mass spectrometry, 1) because it offers the highest broadband resolution of any mass analyzer. This paper addresses the question of the minimum mass resolving power required to provide mass accuracy sufficient to assign a unique elemental composition, C cH hN nO oS s…, from measurement of mass spectral peak position. Over the past five years, FT-ICR MS mass accuracy has improved by about an order of magnitude, based on higher magnetic field strength, conditional averaging of time-domain transients, better mass calibration (spectral segmentation inclusion of a space charge term) radially dispersed excitation phase correction to yield absorption-mode display and new ICR cell segmentation designs.Ī primary goal in mass spectrometry is to identify an analyte, particularly in the presence of other analytes, based on measurement of ion mass. The highest available broadband mass resolving power and mass accuracy is from Fourier transform ion cyclotron resonance mass spectrometry. 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.
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