Method development for compositional analysis of low molecular weight poly(vinyl acetate) by matrix-assisted/laser desorption-mass spectrometry and its application to analysis of chewing gum

by Tisdale, Evgenia; Wilkins, Charles L.

The influence of the sample prepn. parameters (the choice of the solvent and of the matrix:analyte ratio) was investigated and optimal conditions were established for MALDI mass spectrometry anal. of the pristine low mol. wt. polyvinyl acetate (PVAc). It was demonstrated that comparison of polymer's and solvent's Hansen soly. parameters could be used as a guide when choosing the solvent for MALDI sample prepn. The highest intensity PVAc signals were obtained when Et acetate was used as a solvent along with the lowest matrix-analyte ratio (2,5-dihydroxybenzoic acid was used as a matrix in all expts.). The structure of the PVAc was established with high accuracy using the matrix-assisted laser desorption/ionization-Fourier transform mass spectrometry (MALDI-FTMS) anal. It was demonstrated that PVAc undergoes unimol. decompn. by losing acetic acid mols. from its backbone under the conditions of FTMS measurements. No. and wt. av. mol. wts. as well as polydispersity indexes were detd. with both MALDI-TOF and MALDI-FTMS methods. The sample prepn. protocol developed was applied to the anal. of a chewing gum and the mol. wt. and structure of the polyvinyl acetate present in the sample were established. Thus, it was shown that optimized MALDI mass spectrometry could be used successfully for characterization of polyvinyl acetate in com. available chewing gum.

Analytica Chimica Acta
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1873-4324; 0003-2670