Correlation between the spectrum resolution and the peak location accuracy in the isotopomeric cluster

Abstract

An instrument capable of high resolving power is necessary to assure that the m/ z value of the ion being measured is of an ion of a single elemental and/or isotope composition. The accurately determined m/ z value of a mass spectral peak may be a weighted average of multiple ions of different isotopes and/or elemental compositions if the resolving power of the instrument used is insufficient to separate very small differences in m/ z values. Instruments are operated at high resolution (meaning a resolving power R = M/Δ m ≥ 10,000), medium resolution (5000 ≤ R < 10,000), or low resolution (Δ m ≅ 1). A common mistake made in referring to instruments in the high-resolution mode is that they automatically produce measured accurate mass data. What is the dependence of the equipment resolution (resolving power) and masses of peaks in the mass spectrum on peaks location accuracy? The present paper is an attempt at answering the question.