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Characterization of partially transesterified poly(β‐hydroxyalkanoate)s using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Author(s) -
Saeed K. A.,
Ayorinde F. O.,
Eribo B. E.,
Gordon M.,
Collier L.
Publication year - 1999
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(19991015)13:19<1951::aid-rcm737>3.0.co;2-r
Subject(s) - chemistry , mass spectrometry , chromatography , matrix assisted laser desorption/ionization , valerate , desorption , transesterification , catalysis , organic chemistry , adsorption , butyrate , fermentation
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) was used for the characterization of a partially transesterified poly(β‐hydroxyalkanoate), PHA, polymer produced by the bacterial strain Alcaligenes eutrophus using saponified vegetable oils as the sole carbon sources. The transesterification was carried out separately under acidic and basic conditions to obtain PHA oligomers weighing less than 10 kDa. The intact oligomers were detected in their cationized [M + Na] + and [M + K] + forms by MALDI‐TOFMS. A composition analysis, using the MALDI‐TOF spectra, indicate that the oligomers obtained via acid catalysis were terminated with a methyl 3‐hydroxybutyrate end group, and those obtained by base catalysis had a methyl crotonate (olefinic) termination. In addition to HB (hydroxy butyrate), the oligomers were found to contain a small percentage of HV (hydroxy valerate). This was independently confirmed using gas chromatography/mass spectrometry (GC/MS). In comparison, the analysis of a commercial PHA polymer, transesterified under identical conditions, only showed the presence of HB, i.e. a pure PHB homopolymer. Copyright © 1999 John Wiley & Sons, Ltd.