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Matrix‐assisted laser desorption/ionization time‐of‐flight vs. fast‐atom bombardment and electrospray ionization mass spectrometry in the structural characterization of bacterial poly(3‐hydroxyalkanoates)
Author(s) -
Impallomeni Giuseppe,
Ballistreri Alberto,
Carnemolla Giovanni Marco,
Franco Domenico,
Guglielmino Salvatore P. P.
Publication year - 2015
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.7168
Subject(s) - chemistry , mass spectrometry , fast atom bombardment , electrospray ionization , matrix assisted laser desorption/ionization , ionization , analytical chemistry (journal) , matrix (chemical analysis) , desorption , sample preparation in mass spectrometry , chromatography , ion , organic chemistry , adsorption
Rationale Bacterial poly(3‐hydroxyalkanoates) (PHAs) are an emergent class of plastic materials available from renewable resources. Their properties are strictly correlated with the comonomeric composition and sequence, which may be determined by various mass spectrometry approaches. In this paper we compare fast‐atom bombardment (FAB) and electrospray ionization (ESI) to matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) of partially pyrolyzed samples. Methods We determined the compositions and sequences of the medium‐chain‐length PHAs (mcl‐PHAs) prepared by bacterial fermentation of Pseudomonas aeruginosa ATCC 27853 cultured in media containing fatty acids with 8, 12, 14, 18, and 20 carbon atoms as carbon sources by means of MALDI‐TOFMS of pyrolyzates, and compared the results with those obtained by FAB‐ and ESI‐MS in previous studies. MALDI matrices used were 9‐aminoacridine (9‐AA) and indoleacrylic acid (IAA). Results MALDI‐TOFMS was carried out in negative ion mode when using 9‐AA as a matrix, giving a semi‐quantitative estimation of the 3‐hydroxyacids constituting the PHAs, and in positive mode when using IAA, allowing us, through statistical analysis of the relative intensity of the oligomers generated by pyrolysis, to establish that the polymers obtained are true random copolyesters and not a mixture of homopolymers or copolymers. Conclusions MALDI‐TOFMS in 9‐AA and IAA of partial pyrolyzates of mcl‐PHAs represents a powerful method for the structural analysis of these materials. In comparison with FAB and ESI, MALDI provided an extended mass range with better sensitivity at higher mass and a faster method of analysis. Copyright © 2015 John Wiley & Sons, Ltd.