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Fouquet, Thierry

Publications and source records attributed to Fouquet, Thierry.

3 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Elemental Composition Determinations Using the Abundant Isotope

Elemental compositions are commonly determined from the exact m/z of the monoisotopic peak, which is often the lightest isotope. However, the lightest isotope peak is often weak or absent and the monoisotopic peak can be difficult to identify for organometallics, polyhalogenated compounds, or large molecules. An alternative approach using the abundant isotope for elemental composition determinations is presented here. .

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2019

Molecular Characterization of High Molecular Weight Polyesters by Matrix-Assisted Laser Desorption/Ionization High-Resolution Time-of-Flight Mass Spectrometry Combined with On-plate Alkaline Degradation and Mass Defect Analysis

Matrix-assisted laser desorption ionization high-resolution time-of-flight mass spectrometry (MALDI HR TOF MS) is a powerful tool for the molecular characterization of industrial polymers. However, accurate mass determination and resolution of isobaric ions are possible for oligomer samples only typically below m/z 3000. To cut long polymer chains into oligomers suitable for high-resolution mass spectrometry, we propose a simple “on-plate” alkaline degradation of polyesters as a sample pretreatment technique prior to the MALDI TOF MS measurement. This pretreatment can be performed on a MALDI target using a small amount of sample (μg or less) and 1 μL of alkaline reagent by simple pipetting. Informative mass spectra in the oligomeric mass range are successfully recorded but complicated by the variation of end-groups and the copolymeric composition of the degradation products. Data processing is assisted by a series of advanced Kendrick mass defect (KMD) analyses recently proposed by the authors to plot visually understandable two-dimensional maps. On-plate degradation pretreatment, high-resolution MALDI TOF MS measurements, and advanced KMD analyses are innovatively combined for the compositional characterization of bacterial poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) and industrial poly(ethylene terephthalate) samples. .

74 ATOMIC AND MOLECULAR PHYSICS↗