title: 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).
abstract: BACKGROUND
  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.
authors.affiliation: Istituto per i Polimeri, Biomateriali e Compositi, Consiglio Nazionale delle Ricerche, Via P. Gaifami 18, 95126, Catania, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Impallomeni
authors.affiliation: Dipartimento di Scienze del Farmaco, Università di Catania, Viale A. Doria 6, 95125, Catania, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Ballistreri
authors.affiliation: Dipartimento di Scienze del Farmaco, Università di Catania, Viale A. Doria 6, 95125, Catania, Italy.
authors.forename: Giovanni Marco
authors.initials: GM
authors.lastname: Carnemolla
authors.affiliation: Dipartimento di Scienze Biologiche ed Ambientali, Università di Messina, sal. Sperone 31, Vll. S. Agata, 98166, Messina, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Franco
authors.affiliation: Dipartimento di Scienze Biologiche ed Ambientali, Università di Messina, sal. Sperone 31, Vll. S. Agata, 98166, Messina, Italy.
authors.forename: Salvatore P P
authors.initials: SP
authors.lastname: Guglielmino
mesh_terms: D054813:Polyhydroxyalkanoates / Q000032:analysis* / Q000737:chemistry*; D011550:Pseudomonas aeruginosa / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D054813:Polyhydroxyalkanoates