Separation, identification, and confirmation of cyclic and tadpole macromolecules via UPLC-MS/MS
Separation, identification, and confirmation of cyclic and tadpole macromolecules via UPLC-MS/MS
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通过 UPLC-MS/MS 分离、鉴定和确认环状和蝌蚪大分子
DOI：
10.1039/d2an00208f
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Wesdemiotis, Chrys
中科院分区：
文献类型：
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作者：
O'Neill, Jason M.;Mao, Jialin;Haque, Farihah M.;Barroso-Bujans, Fabienne;Grayson, Scott M.;Wesdemiotis, Chrys
两性离子开环聚合法合成的大环聚缩水甘油基苯基醚（pGPE）通常被线性和蝌蚪状结构的链污染。尽管质谱（MS）分析可以很容易地确认线性副产物的存在，但由于其独特的质量，无法区分环状和蝌蚪状结构，它们分别是单体或二聚体链中通过反咬反应产生的结构异构体。为了克服这个问题，采用超高效反相液相色谱-电喷雾串联质谱（UPLC-ESI-MS/MS）。通过UPLC实现的分离显示，由于其独特的取代基提供的极性增加，蝌蚪异构体在环状结构之前洗脱。蝌蚪与环状物质的比例随着聚合度的增加而增加，与所使用的合成方法一致，因为通过反咬形成蝌蚪结构的潜力在较长的聚合物链中是熵有利的。一旦分离，两种异构体可以通过串联质谱法独立地表征。大环和蝌蚪物种表现出独特的片段化模式，包括每个结构的结构诊断片段。
Macrocyclic poly(glycidyl phenyl ether) (pGPE) synthesized via zwitterionic ring opening polymerization is typically contaminated by chains with linear and tadpole architecture. Although mass spectrometry (MS) analysis can readily confirm the presence of the linear byproduct, due to its unique mass, it is unable to differentiate between the cyclic and tadpole structures, which are constitutional isomers produced by backbiting reactions in monomeric or dimeric chains, respectively. To overcome this problem, ultraperformance reversed-phase liquid chromatography interfaced with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) was employed. The separation achieved by UPLC revealed that the tadpole isomer elutes before the cyclic structure because of the increased polarity afforded by its distinctive substituents. The ratio of tadpole to cyclic species increased with the degree of polymerization, in agreement with the synthetic method used, as the potential for forming tadpole structures by backbiting is entropically favored in longer polymer chains. Once separated, the two isomers could be independently characterized by tandem mass spectrometry. The macrocyclic and tadpole species exhibit unique fragmentation patterns, including structurally diagnostic fragments for each structure.