Negative mode MS/MS to read digital information encoded in sequence-defined oligo(urethane)s: A mechanistic study

International audienceMS/MS sequencing is an unrivaled technique to decipher binary information chemically encoded in the backbone of sequence-controlled synthetic polymers constructed with two co-monomers of different mass, arbitrarily designated as the 0- and 1-bit of the ASCII alphabet. Efficiency of this "reading" step relies however on the simplicity of MS/MS patterns, which depends on both polymer chemistry and chain length. In this context, polyurethanes (PUs) were very promising candidates as dissociation of small deprotonated oligomers (n \\textless 8) yielded a single fragment series. The carbamate bond cleavage reaction was hence studied in details to tentatively anticipate the CID behavior of longer chains prior to optimizing their synthesis. In spite of the simplicity of MS/MS spectra, three different mechanisms were evidenced; however, they were not expected to induce MS/MS complexity when activating longer chains, as verified for sequence-controlled PUs containing up to two bytes of information (i.e., 16 co-monomers). In contrast, the ionization step appeared to be an issue: deprotonation yield of the end-group in negative ion mode electrospray was observed to strongly decrease as PU chain length increases. This sensitivity issue was addressed by introducing a second acidic end-group to allow doubly deprotonated oligomers with no impact on their CID behavior. (C) 2017 Elsevier B.V. All rights reserved

Ion Mobility Spectrometry - Mass Spectrometry Coupling for Synthetic Polymers.

MEDLINE:31658387This review covers applications of ion mobility spectrometry (IMS) hyphenated to mass spectrometry (MS) in the field of synthetic polymers

Sequence-coded ATRP macroinitiators

International audienceSequence-coded oligourethanes were tested as macroinitiators for the atom transfer radical polymerization (ATRP) of styrene. These oligomers were synthesized by solid-phase orthogonal iterative chemistry and transformed into ATRP initiators using a three-step modification procedure. A controlled radical polymerization behavior was observed with these macroinitiators, thus opening interesting opportunies for the synthesis of macromolecular architectures containing sequence-defined segments

Differentiation of gonyautoxins by ion mobility - mass spectrometry; a cationization study

Gonyautoxins are potent natural neurotoxic analogues of saxitoxin. Due to their biological activity and submilligram lethal dose for man, fast and efficient methods are required for their characterization. Recent advances in ion mobility-mass spectrometry (IM-MS) showed that differentiation of isomers could be achieved using specific experimental conditions involving particular buffer gases as well as cationic species. In this work, IM-MS experiments were carried out using alkali metal ions (Met = Li+, Na+ or K+) and different buffer gases (N2, N2O and CO2) to improve the differentiation of gonyautoxin isomers. The separation of [GTX + Met]+ ion was achieved for GTX2/3 and GTX1/4 from their Na or K adducts. For dcGTX2/3, the ion mobility separation can only be obtained with peak to peak resolution (Rp-p) close to 1 from the [GTXs + Met − H2O]+ species. To understand the gas phase conformation of the different diastereomers, density functional theory (DFT) calculations were performed. IM separation, and collision cross sections on [GTXs + Met]+ and [GTXs + Met − H2O]+ are reported for the first time