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Analysis of Degraded Polymethyl Methacrylate by UV Irradiation - MSTips 324

Polymers can be degraded by the effects of light, oxygen, heat, etc. so it is important to understand how the polymer structures change during degradation. Pyrolysis gas chromatograph quadrupole mass spectrometer (Py-GC-QMS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOFMS) are powerful tools for analyzing polymeric materials. Py-GC-QMS is a method that instantaneously heats a sample with a pyrolyzer and then analyzes the pyrolysis products by GC-MS. Since most of the pyrolysis products are related to monomers and dimers, this technique allows for easy identification of the polymer substructures which is useful for identifying changes to the polymer when degradation occurs. MALDI-TOFMS involves a soft ionization technique that can directly ionize and analyze the intact polymer molecules and often produces singly-charged ions even for high molecular weight compounds. As a result, the m/z axis of the mass spectrum is equal to the mass of the ions, thus making it easy to interpret polymer distributions. Additionally, when MALDI is used with a high-resolution TOFMS, the accurate mass of each ion in the polymer series can be used to calculate their elemental compositions. Moreover, the molecular weight distribution of polymers can be calculated from the ion intensity distribution. In this work, we used Py-GC-QMS and high-resolution MALDI-TOFMS to evaluate the effects of UV irradiation on polymethyl methacrylate (PMMA).

Fraction base-KMD plots for a high-MW - S3000 - MSTips - 283

High molecular weight polymers are often MS-silent due to their inherent high dispersity (DM) or detected in the high mass range with low resolving power. An "on-plate" alkaline degradation has thus been developed as a sample pre-treatment on the MALDI target with tenths of ng of polymer to cut long industrial polyester chains into short oligomers amenable to MALDI-HRMS.

High Sensitivity Analysis of Intact Proteins using Linear TOF

The JMS-S3000 SpiralTOF has a unique 17m flight path that offers then highest resolution MALDI-TOF MS system currently available. However, ions with a very short lifetime or that undergo spontaneous dissociation during their flight cannot be detected by the SpiralTOF (or a conventional reflection TOF). To address this situation, the SpiralTOF with Linear TOF option can be used for the high sensitivity analysis of intact proteins.

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Corona - Glow Discharge (DART Ion Source)

February 22, 2020
2165