Characterization of poly[(R)-3-hydroxybutyrate-co-ε-caprolactone] copolymers by matrix-assisted laser desorption/ionization time-of-flight and electrospray ionization mass spectrometry
Article first published online: 23 JAN 2006
Copyright © 2006 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 20, Issue 4, pages 568–576, 28 February 2006
How to Cite
Alicata, R., Barbuzzi, T., Giuffrida, M. and Ballistreri, A. (2006), Characterization of poly[(R)-3-hydroxybutyrate-co-ε-caprolactone] copolymers by matrix-assisted laser desorption/ionization time-of-flight and electrospray ionization mass spectrometry. Rapid Commun. Mass Spectrom., 20: 568–576. doi: 10.1002/rcm.2342
- Issue published online: 23 JAN 2006
- Article first published online: 23 JAN 2006
- Manuscript Revised: 11 DEC 2005
- Manuscript Accepted: 11 DEC 2005
- Manuscript Received: 27 OCT 2005
- National Council of Research (CNR, Rome)
- Ministry of Education, University and Research (MIUR, Rome). Grant Number: PRIN 2004
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) of narrowly dispersed molecular weight gel permeation chromatography (GPC) fractions was used to characterize random and microblock poly[(R)-3-hydroxybutyrate-co-ε-caprolactone] [P(HB-co-CL)] copolymers obtained via the acid-catalyzed transesterification of the corresponding homopolymers, poly([(R)-3-hydroxybutyrate] (PHB) and poly(ε-caprolactone) (PCL). High-quality mass spectra were obtained, which made it possible to establish the nature of the polymer end groups. Besides the carboxylic termination, two other moieties were found: alcoholic and tosyl end groups. MALDI mass spectra of CL-rich samples possessed mostly tosyl end groups, while HB-rich samples possessed mostly alcoholic end groups, showing that the tosyl moiety is linked prevalently to CL terminal units. The higher resolution of electrospray ionization (ESI) mass spectra of lower molecular weight GPC fractions permitted the identification of the different oligomer species hypothesized in the assignment of the corresponding MALDI mass spectra. Partial methanolysis of these copolymers was explored as a method of producing mixed HB-CL oligomers to be utilized as new synthons, possessing a minor number of chiral centers from those obtained from hydrolysis of biotechnologically synthesized poly(hydroxyalkanoates) (PHAs). Copyright © 2006 John Wiley & Sons, Ltd.