Related Articles

• Dynamic Transformation Between Covalent Organic Frameworks And Discrete Organic Cages

  We propose a dynamic covalent chemistry (DCC)-induced linker exchange strategy for the structural transformation between covalent organic frameworks (COFs) and cages for the first time. Studies have shown that the COF-to-cage and cage-to-COF transformations were realized by using borate bonds and imine bonds, respectively, as linkages. Self-sorting experiments suggested that borate cages and imine COFs are thermodynamic minimum compounds. This research builds a bridge between discrete and polymeric organic scaffolds and broadens the knowledge of chemistry and materials for porous materials science.
• MS imaging for visualizing synthetic polymers combined with KMD - MSTips - 306

  In this report, we have combined this method with the Kendrick Mass Defect (KMD) method to effectively visualize polymer series mixtures.
• Structural Characterization of Polymers by MALDI Spiral- TOF Mass Spectrometry Combined with Kendrick Mass Defect Analysis

  High-resolution mass spectrometry (HRMS) continues to play an important role in the compositional characterization of larger organic molecules. In the field of polymer characterization, however, the application of HRMS has made only slow progress because of lower compatibility between matrix-assisted laser desorption/ionization (MALDI) and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICRMS). In this study, a newly developed type of MALDI high-resolution time-of-flight mass spectrometry (TOFMS) with a spiral ion trajectory (MALDI spiral-TOFMS) was applied to the structural and compositional characterization of polymers. To create a graphical distribution of polymer components on a two-dimensional plot converted from complex mass spectra, we adopted a slightly modified Kendrick mass defect (KMD) analysis based on accurate masses determined using spiral-TOFMS. By setting the Kendrick mass scale based on the mass of the repeating units of a given polymer, components with common repeat units lined up in the horizontal direction on the KMD plot, whereas those components with different structures were shifted vertically. This combination of MALDI spiral-TOFMS measurement and KMD analysis enabled the successful discrimination of the polymer components in a blend of poly(alkylene oxide)s, the compositional analysis of poly(ethylene oxide)/poly(propylene oxide) block copolymers, and profiling of the end-group distribution of poly(ε- caprolactone)s synthesized under different conditions.
• Analysis of Organic Thin Films by the Laser Desorption/Ionization Method Using the JMS-S3000 “SpiralTOF”

  Laser Desorption/ Ionization-Time of Flight Mass Spectrometry (LDI-TOFMS) is generally used for analysis of organic compounds because this technique generates little fragmentation of molecular ions at ionization. It makes possible to obtain information on molecular weights and molecular structures in organic compounds. In particular, a technique which uses the matrix compounds for enhancing ionization efficiency is well known as Matrix-Assisted Laser Desorption/ Ionization-Time of Flight Mass Spectrometry (MALDI-TOFMS). This technique is widely used in the bio markets owing to its capability of ionizing proteins and peptides with the molecular weights of several thousands to several hundreds of thousands. The MALDI-TOFMS is also utilized for analysis of synthetic polymers. In many cases, LDI-TOFMS and MALDI-TOFMS have been used to estimate the molecular weights of organic compounds in solution. But very recently, techniques of imaging mass spectrometry, which controls the laser irradiation position by two-dimensional scan to acquire mass spectra for visualizing localization of chemical compounds with specific molecular weights, have been improved. The application of this innovative technique is increasingly spreading in the bio markets. The technology of Imaging Mass Spectrometry has been advancing for analyzing biological tissue sections, but in the future, it is expected to develop toward the material science markets. It is noted that various surface analytical techniques are already available in the material science markets. In order to study the advantages of LDI-TOFMS as one of effective surface analysis tools, it is essential to consider the complementary analysis of LDI-TOFMS with the existing surface analytical techniques. In this article, the advantages of using LDI-TOFMS for analyzing organic lightemitting diode material thin films, in accordance with comparison with Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy/Energy-Dispersive X-Ray Spectroscopy (SEM/EDS), have been studied. In addition, since LDI-TOFMS is a destructive analytical technique, the influence on the sample surface caused by LDI-TOFMS was also examined.
• Application of High-Resolution MALDI-TOFMS with a Spiral Ion Trajectory for the Structural Characterization of Free Radical Polymerized Methacrylate Ester Copolymers

  The structural characterization of copolymers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) remains a challenging task, since their random comonomer distribution creates very complicated mass spectra. In this study, a high-resolution TOF mass spectrometer with a spiral ion trajectory was applied to the structural and compositional characterization of free radical copolymerized poly(methyl methacrylate-co-tert-butyl methacrylate), poly(MMA-co-tBMA)s in ethyl lactate acting as a chain transfer agent. Virtually complete peak assignments of the isobaric components within the poly(MMA-co-tBMA)s served to identify the end-group combinations and copolymer compositions of individual copolymer components, allowing the distributions of comonomer compositions and six types of end-group combinations to be evaluated.
• “Remainders of KM” plot for polymers using msRepeatFinder: Intuitive display of High energy collision induced dissociation mass spectra acquired by SpiralTOF™/TOF

  Tandem mass spectrometry of polymer ions provides valuable information about the nature of individual end-groups, chain architecture (linear / cyclic / branched) and copolymeric microstructure. Using matrix-assisted laser desorption ionization (MALDI) with high energy collision-induced dissociation (HE-CID) tandem time-of-flight analysis (TOF/TOF) can be advantageous for MS/MS polymer analysis. However, the interpretation of the resulting mass spectrum may not be obvious when a number of ion series with low intensity signals are present. In this work, a “remainders of Kendrick mass” (RKM) analysis is used as a rapid post-acquisition data processing tool for TOF/TOF mass spectra in order to visualize and filter the ion series instantly via intuitive point alignments.