A general method for quantitative measurement of molecular mass distribution by mass spectrometry

Abstract

A method is presented to test whether the conversion of the mass spectrum of a polydisperse analyte to its molecular mass distribution is quantitative. Mixtures of samples with different average molecular masses, coupled with a Taylor's expansion mathematical formalism, were used to ascertain the reliability of molecular mass distributions derived from mass spectra. Additionally, the method describes how the molecular mass distributions may be corrected if the degree of mass bias is within certain defined limits. This method was demonstrated on polydisperse samples of C 60 fullerenes functionalized with ethylpyrrolidine groups measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; however, it is applicable to any polydisperse analyte and mass spectrometric method as long as spectrum resolution allows individual oligomers to be identified. Mass spectra of the derivatized fullerenes taken in positive ion mode were shown to give an accurate measurement of the molecular mass distribution while those taken in negative ion mode were not. Differences in the mechanisms for ion formation are used to explain the discrepancy.Official

Mass Spectrometry Studies of the Retro-Cycloaddition Reaction of Pyrrolidino and 2-Pyrazolinofullerene Derivatives Under Negative ESI Conditions

“…Moreover, derivatized fullerenes covalently bound to silica particles has been used as thin layer for LDI mass spectrometry analysis of low-mass range molecules [12], and to serve as polydisperse analyte whose mass spectra give an accurate measurement of the molecular mass distribution [13]. Although the spectrometric fragments formed in the oxidation reactions of some fluorinated fullerenes have been observed under EI conditions [14], fullerenes and their functionalized derivatives are mainly analyzed under LDI and ESI conditions.…”

Challenges in polysorbate characterization by mass spectrometry

“…Finally, it is well known that polydisperse distributions are frequently distorted in MALDI spectra, with the signals at higher mass suppressed . In addition, due to the variety of species present in polysorbates, care must be taken in measuring the relative amount of various species, as the effects discussed above can easily result in a skewed picture of the material.…”

Quantitative measurement of the polydispersity in the extent of functionalization of glass‐forming calix[4]resorcinarenes

“…When applied, the correction factor produces a final, more accurate distribution. Full details of the Taylor's expansion method can be found in previous publications; 12,13 here only the pertinent results of that mathematical derivation will be presented. In general, if the experiments are conducted in the linear range of target concentration versus signal intensity for each oligomer i then:…”

“…When applied, the correction factor produces a final, more accurate distribution. Full details of the Taylor's expansion method can be found in previous publications;12, 13 here only the pertinent results of that mathematical derivation will be presented.…”

“…The quantitative method uses a Taylor's expansion approach to develop a calibration curve to correct the ion intensities in the mass spectrum leading to a more reliable measure of the polydispersity of the extent of functionalization. Only the results of this mathematical derivation will be used here; full details can be found elsewhere 12, 13…”