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Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry with size‐exclusion chromatographic fractionation for structural characterization of synthetic aliphatic copolyesters
Author(s) -
Adamus Grażyna,
Rizzarelli Paola,
Montaudo Maurizio S.,
Kowalczuk Marek,
Montaudo Giorgio
Publication year - 2006
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.2365
Subject(s) - copolyester , chemistry , mass spectrometry , size exclusion chromatography , macromolecule , mass spectrum , copolymer , matrix assisted laser desorption/ionization , transesterification , desorption , time of flight mass spectrometry , polymer chemistry , polymer , chromatography , analytical chemistry (journal) , ionization , polyester , organic chemistry , ion , catalysis , biochemistry , adsorption , enzyme
We report matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and off‐line coupling of size‐exclusion chromatography with MALDI‐TOFMS analysis (SEC/MALDI‐TOFMS) methods for the detailed characterization of poly[(R,S)‐3‐hydroxybutyrate‐co‐L‐lactic acid], P[(R,S)‐3HB‐co‐LA], and poly[(R,S)‐3‐hydroxybutyrate‐co‐ ε ‐caprolactone], P[(R,S)‐3HB‐co‐CL], copolymer samples which are expected to be used in special medical application as scaffolds for cartilage and soft tissue engineering. The novel copolyesters contained randomly distributed (R,S)‐3‐hydroxybutyrate structural units, were synthesized by transesterification of the corresponding homopolymers, i.e. atactic poly[(R,S)‐3‐hydroxybutyrate], a‐PHB, and poly(L‐Lactide) (PLLA) or poly( ε ‐caprolactone) (PCL), respectively. The MS methods used for the characterization of the resulting polydisperse copolyester samples were supported by classical methods (NMR, SEC). The structures of individual copolyester macromolecules, including end‐group chemical structures, were established using initially MALDI‐TOFMS and then SEC/MALDI‐TOFMS. The compositions of the copolyesters were determined by two methods, namely based on 1 H NMR and MALDI‐TOF spectra. The two sets of values showed good agreement. The sequence distribution was determined using the signal intensities of individual copolyester macromolecules, which appeared in MALDI‐TOF mass spectra. Furthermore, sequence analysis gave information about the degree of transesterification. The copolyesters synthesized, with only one exception, were demonstrated to be almost random, which implies that the ester‐ester exchange was close to completion. Copyright © 2006 John Wiley & Sons, Ltd.