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Molecular weight distribution of poly(dimethylsiloxane) by combining matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry with gel‐permeation chromatography fractionation
Author(s) -
Montaudo Giorgio,
Montaudo Maurizio S.,
Puglisi Concetto,
Samperi Filippo
Publication year - 1995
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/rcm.1290091215
Subject(s) - chemistry , gel permeation chromatography , chromatography , fractionation , mass spectrometry , molar mass distribution , permeation , desorption , matrix assisted laser desorption/ionization , matrix (chemical analysis) , analytical chemistry (journal) , polymer , membrane , organic chemistry , adsorption , biochemistry
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) allows detection of large molecules such as those present in synthetic and natural macromolecules. Until recently, it was reported that MALDI‐TOF measurements can provide correct molecular weight (MW) estimates only for nearly monodisperse polymer samples. We have now developed a methodology for polydisperse samples. We recorded the gel‐permeation chromatography (GPC) trace of a polydisperse polymeric sample of poly(dimethylsiloxane) (PDMS), collecting 42 fractions. Selected fractions were analyzed by MALDI‐TOF and the average MW of each fraction was determined, allowing a calibration of GPC curves against absolute MW. The calibrated GPC trace was then used to compute average MW and molecular‐weight distribution (MWD) of the unfractionated poly(dimethylsiloxane) sample. In the spectra of low molecular‐weight fractions, the resolution is high enough to resolve the contributions of the various PDMS oligomers as separate signals.