The evaluation of complex mass spectra requires effective data processing and visualization methods. The recently invented data mining procedure, the mass-remainder analysis (MARA), was further developed for use in the mass spectrometry of polymer blends containing copolymers. MARA is based on the calculation of the mass remainder after dividing by the exact mass of a base unit, e.g., the repeat unit of a polymer. Our improved method, the multistep mass-remainder analysis (M-MARA), performs sequential calculations of the remainders. The keys of the method are the selection of the base units and visualization by MR3 versus m/z and/or MR2 versus MR1 plots, where MR i is the mass remainder of the ith step. The proposed method eliminates the periodicities present in a complex system and therefore provides highly simplified plots. The effectiveness of the M-MARA method was demonstrated by the analysis of polylactide/polycaprolactone and various ethylene oxide/propylene oxide copolymer samples.

The data processing and visualization methods are of paramount importance in the mass spectrometry of copolymers. To determine the copolymer composition, in this article, a robust algorithm is proposed for the compositional assignment and for the estimation of the relative abundance of each species present in copolymer mass spectra. Our homemade software enables the accurate calculation of the compositional drift, i.e., the variation of copolymer composition with the polymer chain lengths. Furthermore, we introduce a novel copolymer quantity, namely, the polydispersity (also called as dispersity) ratio (PDR) of the comonomers, and establish a characteristic relationship between the shape of the composition drift curves and the PDR values. This relation allows, for instance, a quick visual recognition of the presence of diblocks in a triblock copolymer by means of mass spectrometry. Our approach is demonstrated by the analysis of various poloxamers, i.e., polyethylene oxide (PEO)−polypropylene oxide (PPO) block copolymers up to the average molecular weight of approximately 4000 g/mol. The determined number-average molecular weights and the ethylene oxide contents were also confirmed by nuclear magnetic resonance spectroscopy. Dynamic light scattering experiments revealed that small variations in the copolymer composition significantly affect the properties of the copolymer.

The characteristics of the polyalkylene oxide polyether polyols highly influence the properties of final polyurethane products. As a novel approach, in order to gain structural information, the recently invented data mining procedures, namely the Mass-remainder analysis (MARA) and the Multistep Mass-remainder analysis (M-MARA) are successfully applied for the processing of tandem mass spectrometry (MS/MS) data of various industrially important polyether polyols. M-MARA yields an ultra-simplified graphical representation of the MS/MS spectra and sorts the product ions based on their double bond equivalent (DBE) values. The maximum DBE values unambiguously differentiate among the various polyether polyols. Accordingly, the characteristic DBE values were 0, 1 for the linear diol polyethers, 0, 1, 2 for the three-arm, and 0, 1 2, 3, 4 for the six-arm polyether polyols. In addition, it was also found that the characteristic collision energy necessary for the optimum fragmentation yield depended linearly on the molecular weight of the polyols. This relationship offers an easy way for instrument tuning to gain structural information.

Matrix-assisted laser desorption ionization and electrospray ionization mass spectrometry (MALDI-MS and ESI-MS) were used for the characterization of epoxidized soybean and linseed oils, which are important raw materials in the biopolymer production. The recently invented data mining approach, mass-remainder analysis (MARA), was implemented for the analysis of these types of complex natural systems. Different epoxidized triglyceride mass spectral peak series were identified, and the number of carbon atoms and epoxide groups was determined. The fragmentation mechanisms of the epoxidized triglyceride (ETG) adducts formed with different cations (such as H+, Na+, Li+, and NH4+) were explored. As a novel approach, the evaluation of the clear fragmentation pathways of the sodiated ETG adducts enabled the estimation of the epoxidized fatty acid compositions of these types of oils by MS/MS.

Polyethylene glycol 400 (PEG 400) was used as a permeability probe to examine the gastrointestinal tract which can be involved in the pathogenesis of some inflammatory and autoimmune diseases. A novel methodology was developed and validated for the quantitation of PEG 400 excreted in human urine after oral administration using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The excretion ratios were determined for the most intense ions corresponding to nine PEG 400 oligomers. The relative error of accuracy was between –6.0% and 8.5%, and the relative standard deviation (RSD) of the precision was below 15%. Our method was successfully applied in a large-scale experimental study involving nearly two hundred volunteers. Due to the large number of measurements, detailed and reliable statistical analysis was performed. No significant difference was found between the male and female group of volunteers at 0.05 significance level, except the two largest PEG oligomers. However, the average excretion ratios of the male volunteers are greater than that of the women for all the nine PEG oligomers, suggesting a difference in the intestinal permeability between men and women.