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Rationale: Synthesis of copolymer is one of the major approaches to establish sophisticated polymers. In copolymer analysis in mass spectrometry (MS), an increase in the number of monomer unit species and/or the polymer molecular weight results in complex mass spectra, and a method is required to solve this problem. Methods: In this study, electrospray ionization‐ion mobility spectrometry‐mass spectrometry was employed to analyze styrene/methyl methacrylate/n‐butyl acrylate (St/MMA/nBA) terpolymers via Kendrick mass defect (KMD) analysis. An expanded Fourier transform‐based noise reduction method for the copolymer was developed to improve the decrease in the signal/noise ratio observed in the higher m/z region. Results: Low‐mass terpolymers (0.7 kDa) were identified by comparing the observed and theoretical results using a two‐dimensional KMD plot. For the 1.5 kDa terpolymer, the signal overlap, of which KMD value was not matched with the theoretical one, was interpreted by the shift from the theoretical value in the KMD plot. For the 3.0 kDa terpolymers, the compositional candidates were determined by the prediction based on the compositional information of low‐mass terpolymers previously analyzed. The 4.5 kDa terpolymer was interpreted after the expanded noise filtering. Conclusions: The terpolymers, whose molecular weight was up to 4.5 kDa, were successfully characterized at a molecular level. The dependency of the St/MMA/nBA composition on molecular weight was observed; that is, the nBA content decreased with an increase in the molecular weight. [ABSTRACT FROM AUTHOR]

Rationale: We recently developed the characterization method for synthetic polymers weighing more than a few tens of kilodalton using electrospray ionization‐ion mobility spectrometry‐tandem mass spectrometry, in which the m/z value of the most abundant peak was used for characterization. However, the identification of the most abundant peak from the isotopic peaks was often difficult due to the background noise. Methods: Here, we employed a noise reduction method using Fourier transform (FT) filtering. In the power spectrum obtained using FT of the mass spectrum of the multiple charged analytes, the significant signals in the low‐frequency region and at frequency z are observed for the analytes of z charges. When the signals in both regions were used for inversed FT (i.e., the signals in other regions were zero padded), a noise‐filtered mass spectrum was obtained. Results: In the analysis of poly(methylmethacrylate)s weighing 13–17 kDa, mass spectra without noise filtering with relatively high‐intensity noise (than signal) were complicated to identify the most abundant peak. On the contrary, the most abundant peak was clearly identified from the mass spectra after FT‐based noise filtering, and end group composition was estimated successfully. Conclusions: The proposed FT‐based noise filtering for the mass spectrum is effective to characterize multiply charged synthetic polymers weighing more than a few tens of kilodalton using electrospray ionization‐ion mobility spectrometry‐tandem mass spectrometry. [ABSTRACT FROM AUTHOR]

The separation of the structural isomers of OLED materials was carried out by using high performance liquid chromatography‐mass spectrometry (HPLC‐MS) and ion mobility‐mass spectrometry (IM‐MS). Almost all isomeric OLED materials were separated by using HPLC, however, some isomers were not distinguished with each other. On the other hand, by using IM, inseparable isomers by HPLC were separated and the structural information was obtained by MS/MS technique. [ABSTRACT FROM AUTHOR]

Rationale: Analyzing polymer end groups using pyrolysis (Py) gas chromatography/mass spectrometry (GC/MS) in multi‐component polymer samples is not an easy task because of the insufficient sensitivity, selectivity, and mass resolution of conventional Py‐GC/MS systems. Methods: A new Py‐GC/MS system using an atmospheric pressure chemical ionization (APCI) source combined with high‐resolution time‐of‐flight mass spectrometry (TOFMS) was used for end‐group analysis of a methyl methacrylate (MMA)‐styrene (St)‐butyl acrylate (BA) terpolymer (P (MMA‐St‐BA)), which was radically polymerized using 2,2′‐azobis(2‐methylbutyronitrile) (AMBN) as an initiator. Results: Five possible pyrolyzates, comprising an AMBN fragment and a monomer unit, formed during the initiation reactions from one of the three types of end groups, were selectively detected and exclusively identified in their respective extracted ion chromatograms for molecule‐related ions, such as M+ and [M + H]+, with a narrow mass window of ±2 milli m/z units. Conclusions: It was demonstrated that Py‐APCI‐TOFMS is a powerful technique to characterize in detail the complex end groups in multi‐component polymer samples, because of the soft ionization nature of APCI and the high mass resolution of TOFMS. [ABSTRACT FROM AUTHOR]

Significant peak width reductions, or peak height enhancements, of angiotensins were observed when a high voltage was applied to hydrophilic interaction pressurized capillary electrochromatography using gradient elution with mobile phases containing perchloric acid. The investigation using a contactless conductivity detector revealed that perchloric acid was adsorbed on the surface of the stationary phase, when the acetonitrile content in the mobile phase was high, and released from the stationary phase by increasing the water content during a gradient procedure. The released perchloric acid formed a highly concentrated zone moving from the column inlet to the outlet. The electrochromatographic behavior of the analytes, primarily electrophoretic migration, was changed in this zone. As a consequence of the significant variation in migration velocity of the analytes, the sample band width was reduced similar fashion to on-capillary concentration in capillary electrophoresis. Using this result, the reduction of band width and enhancement in separation efficiency was demonstrated in reversed-phase pressurized electrochromatography, in which the conductivity of the mobile phase was significantly altered using a step gradient. The resolution between benzoic acid and 1-naphthalene sulfonic acid was successfully improved from 2.7 to 4.3 by using the band width reduction method based on field-amplified stacking. [ABSTRACT FROM AUTHOR]

A method of simultaneous separation of water- and fat-soluble vitamins using pressure-assisted CEC with a methacrylate-based capillary monolithic column was developed. In the proposed method, water-soluble vitamins were mainly separated electrophoretically, while fat soluble-ones were separated chromatographically by the interaction with a methacrylate-based monolith. A mixture of six water-soluble and four fat-soluble vitamins was separated simultaneously within 20 min with an isocratic elution using 1 M formic acid (pH 1.9)/acetonitrile (30:70, v/v) containing 10 mM ammonium formate as a mobile phase. When the method was applied to a commercial multivitamin tablet and a spiked one, the vitamins were successfully analyzed, and no influence of the matrix contained in the tablet was observed. [ABSTRACT FROM AUTHOR]