The rapid characterisation of poly(ethylene glycol) oligomers using desorption electrospray ionisation tandem mass spectrometry combined with novel product ion peak assignment software.

Jonathan P Williams, Gillian R Hilton, Konstantinos Thalassinos, Anthony T Jackson, James H Scrivens

Index: Rapid Commun. Mass Spectrom. 21(11) , 1693-704, (2007)

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Abstract

A rapid method for the characterisation of polyglycol esters and ethers is described which uses accurate mass desorption electrospray ionisation (DESI) quadrupole time-of-flight mass spectrometry (Q-ToFMS). The results are combined with newly developed software which aids the interpretation of product ions produced using collision-induced dissociation (CID) of selected precursor ions. The poly(ethylene glycol) (PEG) samples analysed were PEG dibenzoate, PEG monooleate, PEG butyl ether, PEG bis(2-ethyl hexanoate) and PEG diacrylate. Lithium metal was used for cationisation of the PEG oligomers since it yielded the most useful structural information compared with other group I metals. The full scan mass spectra and product ion mass spectra were all obtained in <5 s. Interpretation of the MS/MS product ion spectra, using the product ion interpretation software which incorporates previously developed fragmentation rules, was carried out in <1 s.