Characterization of different poly(2‐oxazoline) block copolymers by MALDI‐TOF MS/MS and ESI‐Q‐TOF MS/MS

Abstract

A complete library of poly(2‐oxazoline) block copolymers was synthesized via cationic ring opening polymerization for the characterization by two different soft ionization techniques, namely matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and electrospray ionization quadrupole time‐of‐flight mass spectrometry (ESI‐Q‐TOF MS). In addition, a detailed characterization was performed by tandem MS to gain more structural information about the block copolymer composition and its fragmentation behavior. The fragmentation of the poly(2‐oxazoline) block copolymers revealed the desired polymer structure and possible side reactions, which could be explained by different mechanisms, like 1,4‐ethylene or hydrogen elimination and the McLafferty +1 rearrangement. Polymers with aryl side groups showed less fragmentation due to their higher stability compared to polymers with alkyl side groups. These insights represent a further step toward the construction of a library with fragments and their fragmentation pathways for synthetic polymers, following the successful examples in proteomics. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

Collision‐induced dissociation study of poly(2‐ethyl‐2‐oxazoline) using survival yields and breakdown curves

“…hydrogen and ethylene eliminations, distinctly from our results for the protonated oligomers (in our case charge‐induced fragmentations occurred). They also realized that polymerization can lead to the formation of polymers with the following composition: CH 3 (C 5 H 9 NO) n NHCH 2 CH 2 OCOCH 2 CH 3 and a C 3 H 6 O 2 unit (propionic acid) can be eliminated from the chain‐end under mass spectrometric conditions . This would mean that the similar loss observed in our study may also due to the minor presence of such polymers.…”

“…Fragmentation of the sodiated pEtOx was studied earlier with MALDI‐TOF and ESI‐QTOF methods by Schubert et al . They observed mainly charge‐remote dissociations, e.g.…”

Survivorship navigation outcome measures

“…Either a hydroxyl group or a formyl ester is formed and subsequently hydrolyzed. The ester formation also occurs for other POxs 45,46…”

Analysis of different synthetic homopolymers by the use of a new calculation software for tandem mass spectra

“…(c). The complete series A , B , C , D , E , G , H, L and M , including the ′ and ″ ones, and their corresponding fragmentation pathways, have previously been discussed . In addition, the following series Z , Y , N , I , K and O could be assigned as fragmentation possibilities to the investigated homopolymers.…”

“…The syntheses of these polymers were initiated with methyl tosylate and the polymers were end‐capped with water, which could be confirmed by MALDI‐TOF MS and 1 H NMR spectroscopy. Based on already discussed side reactions, two possible end groups can be found for the main distribution . Either a hydroxyl (‐OH) group or an ester end group (‐NHCH 2 CH 2 OCOR) can be formed during the end‐capping process.…”