Analysis of High-Molecular-Weight Polyrotaxanes by MALDI-TOF-MS Using 3-Aminoquinoline-Based Ionic Liquid Matrix
Analysis of High-Molecular-Weight Polyrotaxanes by MALDI-TOF-MS Using 3-Aminoquinoline-Based Ionic Liquid Matrix
复制标题
使用 3-氨基喹啉基离子液体基质通过 MALDI-TOF-MS 分析高分子量聚轮烷
DOI：
10.1021/jasms.9b00084
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发表时间：
2020
影响因子：
3.2
通讯作者：
Kazuaki Kato
中科院分区：
文献类型：
--
作者：
Yuzo Yamazaki;Shuuichi Nakaya;Kohzo Ito;Kazuaki Kato
聚轮烷（PR）是一种项链状的超分子，由环糊精（CD）等环状组分和包覆有粗大端基的螺纹聚合物组成。PR由于与CD分子间交联而表现出特殊的机械性能。在线性PEG链上螺纹的各种CD分子经常被化学基团修饰以增加特定的物理化学性能。一般来说，CD与PEG链之间的化学计量是决定CD基聚轮烷（CD- pr）独特物理性质的重要参数。迄今为止，质谱（MS）已被应用于研究CD- pr的分子分布、CD的修饰和CD的螺纹比。然而，只有分子量（MWs）高达几十kDa的CD- pr可以进行这种分析，而作为工业材料的CD- pr的MW要大得多。本文采用由3-氨基喹啉组成的两种离子液体基质和高质量检测器对pr进行了MALDI-TOF-MS分析。在90-700 kDa范围内，用这种方法成功地分析了高至非常高的MW pr。CD的螺纹比是通过单MW的CD、PEG和PR来估计的。所获得的比率与使用1h NMR获得的比率一致。此外，在γ-环糊精螺纹PR （γCD-PR）中，单链形式的PR与双链形式的PR明显不同，而双链形式的PR只有在γCD-PR中才有可能存在，因为它的宿主腔很大。
Polyrotaxane (PR) is a necklace-like supramolecule composed of cyclic components, such as cyclodextrin (CD), and a threading polymer capped with bulky end groups. PR exhibits peculiar mechanical properties attributed to the intermolecular cross-links with CD. Various CD molecules threaded on a linear PEG chain are often modified with chemical groups to add specific physicochemical properties. In general, the stoichiometry between CD and the PEG chain is a significant parameter that defines the unique physical properties of CD-based polyrotaxane (CD-PR). To date, mass spectrometry (MS) has been applied to investigate the molecular distribution of CD-PR, modifications of CD, and the threaded ratio of CD. However, only molecular weights (MWs) up to several 10s of kDa can be subjected to such analysis, whereas the MW of CD-PR used as industrial materials is much greater. Herein, we applied two ionic liquid matrices composed of 3-aminoquinoline and a high mass detector to analyze PRs using MALDI-TOF-MS. High to very high MW PRs in the range of 90–700 kDa were successfully analyzed using this method. The threaded ratio of CD was estimated from a single MW of CD, PEG, and PR. The ratios obtained were consistent with that obtained using1H NMR. Furthermore, a single-stranded form of PR in γ-cyclodextrin threaded PR (γCD-PR) was clearly distinguished from a double-stranded form, which is only possible in γCD -PR because of its large host cavity.