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Novel Procedure for Molecular Weight Averages Measurement of Polydisperse Polymers Directly from Matrix‐assisted Laser Desorption/Ionization Time‐of‐flight Mass Spectra
Author(s) -
Montaudo Giorgio,
Scamporrino Emilio,
Vitalini Daniele,
Mineo Placido
Publication year - 1996
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(199609)10:12<1551::aid-rcm701>3.0.co;2-7
Subject(s) - dispersity , chemistry , mass spectrum , analytical chemistry (journal) , polymer , molar mass distribution , spectral line , mass spectrometry , ionization , polydimethylsiloxane , chromatography , polymer chemistry , ion , physics , organic chemistry , astronomy
A new method for the determination of reliable molecular weight averages (MW) and polydispersity index (MWD) values for polydisperse polymers, directly analyzing their matrix‐assisted laser/desorption ionization time‐of‐flight (MALDI‐TOF) mass spectra, is reported. Our success is due to the concerted effect of an off‐line procedure of MALDI‐TOF spectrum processing that includes: (i) signal smoothing to improve the recorded traces of the spectra up to high m/z values; (ii) a subtraction of the misleading contribution to the signals introduced by the offset used in spectrum recording; (iii) examination of the spectra up to the highest possible m/z value for a better accuracy in estimating the MW values. To illustrate this method, three polymers with a wide polydispersity index, a polydimethylsiloxane, a polymethylmethacrylate, and a bisphenol‐A copolyether, have been analyzed. Contrary to the general opinion that MW values can be measured directly by MALDI‐TOF only for polymers with a very narrow mass distribution, the data reported here show that our off‐line procedure is also able to measure reliable MW values for polydisperse materials.