Polymer Topology Revealed by Ion Mobility Coupled with Mass Spectrometry
Polymer Topology Revealed by Ion Mobility Coupled with Mass Spectrometry
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DOI：
10.1021/ac502246g
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发表时间：
2014-10-07
影响因子：
7.4
通讯作者：
de Pauw, Edwin
中科院分区：
文献类型：
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作者：
Morsa, Denis;Defize, Thomas;de Pauw, Edwin
超支化和星星状聚合物由于其独特的结构和光化学性质而引起人们极大的兴趣，这为它们在生物医学领域提供了潜在的应用。在这种情况下，开发适当的工具，旨在探测这种聚合物的特定三维特征是至关重要的。在本工作中，离子迁移率与质谱联用，实验得出的结构信息相关的阳离子化的线性和星星形的聚-ε-己内酯作为其电荷状态和链长的函数。两个主要的构象进行了观察和鉴定，使用理论建模。(1)对于长且轻电荷链，其尺寸随聚合物拓扑结构不变的近球形构象;以及（2）对于短且高电荷链，其尺寸随聚合物拓扑结构变化的伸长构象。这些构象进一步证实了碰撞活化实验的基础上的喷射阈值的配位阳离子，根据聚合物链的伸长幅度的变化。最后，溶液和气相构象之间的比较突出了在电喷雾过程的电离和去溶剂化步骤期间具有特定链排列损失的结构的压缩，从而引发了与在转移到质谱仪期间保存分析物结构相关的长期争论的问题。
Hyperbranched and star shaped polymers have raised tremendous interest because of their unusual structural and photochemical properties, which provide them potent applications in various domains, namely in the biomedical field. In this context, the development of adequate tools aiming to probe particular three-dimensional features of such polymers is of crucial importance. In this present work ion mobility coupled with mass spectrometry was used to experimentally derive structural information related to cationized linear and star shaped poly-epsilon-caprolactones as a function of their charge state and chain length. Two major conformation were observed and identified using theoretical modeling. (1) near spherical conformations whose sizes are invariant with the polymer topology for long and lightly charged chains and (2) elongated conformations whose sizes vary with the polymer topology for short and highly charged chains. These conformations were further confirmed by collisional activation experiments based on the ejection thresholds of the coordinated cations that vary according to the elongation the amplitude of the polymer chains. Finally a comparison between solution and gas-phase conformations highlights a compaction of the sgtructure with a loss of specific chain arrangements during the ionization and desolvation steps of the electrospray process, fueling the long-time debated question related to the preservation of the analyte sgtructure during the transfer into the mass spectrometer.