Matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) and the off-line size exclusion chromatography matrix-assisted laser desorption/ionisation (SEC/MALDI-TOF MS) method are regularly used for the detailed structural characterization of biodegradable polymers. MALDI-TOF MS and off-line SEC/MALDI-TOF MS analysis has been applied to the structural characterisation and the molar mass (MM) determination of synthetic and commercial biodegradable homo- and co-polyesters.
Biodegradable polyesters analyzed include poly(butylene succinate) (PBSu), poly(butylene adipate) (PBAd), poly(butylene sebacate) (PBSe) and their copolymers with different compositions; Bionolle 3020 and 3001, Bionolle 1001; 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.
Synthetic biodegradable polymers are commonly analyzed by MALDI-TOF MS to check the presence of all species expected from the method of synthesis. The detection of unexpected species suggests the occurrence of undesirable thermal degradation processes during the melt polycondensation reaction.
Although MALDI is a soft ionization technique, product ion analysis can be performed with a MALDI-TOF mass spectrometer by means of the so-called post source decay (PSD). The MALDI-TOF/TOF (matrix assisted laser desorption ionization/time of flight/time of flight) mass spectrometer is a recent mass spectrometer design that overcomes many of the limitations of PSD and CID in a conventional MALDI instrument. In MALDI-TOF/TOF high velocity ions produced in a high-vacuum pulsed MALDI-TOF are selected with a timed ion gate, collided at kiloelectronvolt energies with gas atoms or molecules, and then further accelerated for analysis in a two-stage reflectron TOF.
Recently, we successfully undertook pioneering studies on fragmentation mechanisms and structural analysis of synthetic biodegradable polymers by matrix-assisted laser desorption ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF/TOF-MS/MS). In particular, we investigated the fragmentation pathways of synthetic aliphatic poly(ester amide) and polyesters, studying the influence of end groups and the collision gas. Furthermore, MALDI-TOF/TOF-MS/MS provided structural information about the ester and amide bond sequences in synthetic poly(ester amide) samples from dimethyl sebacate or sebacic acid and 2-aminoethanol (PEA-Et) or 4-amino-1-butanol (PEA-Bu). Additionally, MALDI-TOF/TOF-MS/MS was employed to investigate the structure of species originated from side reactions during the polymer synthesis.
Related papers:
1. P. Rizzarelli, C. Puglisi, G. Montaudo.
Sequence determination in aliphatic poly(ester amide)s by matrix-assisted laser desorption/ionization time-of-flight and time-of-flight/time-of-flight tandem mass spectrometry
Rapid Commun. Mass Spectrom., 19 (2005) 2407.
2. P. Rizzarelli, C. Puglisi, G. Montaudo.
Matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectra of poly(butylene adipate)
Rapid Commun. Mass Spectrom., 20 (2006) 1683.
3. P. Rizzarelli and C. Puglisi.
Structural characterization of synthetic poly(ester amide) from sebacic acid and 4-amino-1-butanol by matrixassisted laser desorption ionization time-of-flight/time-of-flight tandem mass spectrometry
Rapid Commun. Mass Spectrom., 22 (2008) 739.
Related posters:
1. Maldi tof/tof and maldi tof/tof ms/ms analysis of synthetic poly(ester amide) from sebacic acid and 4-amino-1-butanol
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