Mass-Remainder Analysis (MARA): a New Data Mining Tool for Copolymer Characterization

Abstract

A new data mining method is proposed for the determination of the copolymer composition from moderate/low resolution complex mass spectra. The Mass-remainder analysis (MARA) does not require a "Kendrick-like" transformation to a new mass scale, it is simply based on the calculation of the remainder after dividing by the exact mass of one of the repeat units of the copolymer (e.g., B of an A/B copolymer). Plotting the remainder of this division (MR) versus m/ z the homologous series differing only by a number of base units (e.g., B unit) can be visualized. The number of A units ( n) and subsequently n is assigned to the m/ z peaks using the bijective n, MR mapping. Simultaneously, our algorithm removes the isotopes from the peak list. However, the intensities of the monoisotopes are increased to the value corresponding, approximately, to the total intensity of their isotope peaks. The correction of the mass spectral peak intensities enables the accurate calculation of the usual polymer and copolymer quantities: the molecular weight-average, the number-averaged molecular weight of A and B units, the composition drift, or the bivariate distribution, among others. Our Mass-remainder analysis method was demonstrated by the analysis of various ethylene oxide/propylene oxide copolymers.

Thermal desorption and pyrolysis direct analysis in real time mass spectrometry for qualitative characterization of polymers and polymer additives

“…Peak series differing by the monomer mass may be easily recognized, as in the case of nylon polymers. Mass defect analysis, in particular Kendrick mass analysis may be used to identify characteristic peak series for cases in which the monomer series is not readily evident by inspection, and/or when multiple polymer types are present. …”

Mass Spectrometric Characterization of Epoxidized Vegetable Oils

“…Hence, the mass spectrometric study of complex natural samples requires effective data processing and visualization methods [17]. Recently, we proposed a simple algorithm, mass-remainder analysis (MARA), for the processing of complex copolymer mass spectra [18]. In the first step, MARA assigns a mass remainder (MR) value to the mass spectrum peaks defined by Equation (1), MR = m / z MOD B , where B is the exact mass of a base unit and the modulo (MOD) operation finds the remainder after the division.…”

Automatic peak assignment and visualisation of copolymer mass spectrometry data using the ‘genetic algorithm’

“…Mass remainder analysis (MaRA) as proposed by Nagy et al 49 is similar to the Kendrick mass defect; however. it is much more simplified, utilising the division of a peak by one of the repeat units to allow for the separation of species into visual horizontal rows.…”