Block Length Determination of the Block Copolymer mPEG-b-PS Using MALDI-TOF MS/MS
Block Length Determination of the Block Copolymer mPEG-b-PS Using MALDI-TOF MS/MS
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使用 MALDI-TOF MS/MS 测定嵌段共聚物 mPEG-b-PS 的嵌段长度
DOI：
10.1002/pola.24223
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
U. Schubert
中科院分区：
文献类型：
--
作者：
A. Crecelius;C. R. Becer;K. Knop;U. Schubert
用色谱技术测定嵌段共聚物，特别是两亲性嵌段共聚物的摩尔质量一直是个难题。为此，采用原子转移自由基聚合法(ATRP)合成了甲氧基聚乙二醇聚对苯二甲酸乙二醇酯(mEg-b-PS)，并用尺寸排除色谱法(SEC)和基质辅助激光解吸电离串联质谱仪(MALDI-TOF MS/MS)对其进行了表征。正如预期的那样，在SEC测量中获得了不同的摩尔质量值，这取决于校准标准(聚乙二醇或聚苯乙烯)。相反，MALDI-TOF MS/MS分析允许通过切断聚乙二醇和聚苯乙烯嵌段之间最薄弱的点来测定每个嵌段的摩尔质量。因此，可以获得各个区块的片段。聚乙二醇嵌段表现为解聚反应，而PS嵌段由于多个链断裂而在单体、二聚体和三聚体区域得到碎片。从MALDI-TOF MS/MS谱图中记录的碎片可以计算出聚乙二醇单甲醚和聚乙二醇单甲醚的嵌段长度。此外，MALDI-TOF MS/MS获得的各个嵌段的亚结构的指认是在从相应的均聚物获得的片段的帮助下完成的。2010Wiley期刊公司，J Polym Sci Part A：Polym Chem，2010
The molar mass determination of block copolymers, in particular amphiphilic block copolymers, has been challenging with chromatographic techniques. Therefore, methoxy poly(ethylene glycol)-b-poly(styrene) (mPEG-b-PS) was synthesized by atom transfer radical polymerization (ATRP) and characterized in detail not only by conventional chromatographic techniques, such as size exclusion chromatography (SEC), but also by matrix-assisted laser/desorption ionization tandem mass spectrometry (MALDI-TOF MS/MS). As expected, different molar mass values were obtained in the SEC measurements depending on the calibration standards (either PEG or PS). In contrast, MALDI-TOF MS/MS analysis allowed the molar mass determination of each block, by the scission of the weakest point between the PEG and PS block. Thus, fragments of the individual blocks could be obtained. The PEG block showed a depolymerization reaction, while for the PS block fragments were obtained in the monomeric, dimeric, and trimeric regions as a result of multiple chain scissions. The block length of PEG and PS could be calculated from the fragments recorded in the MALDI-TOF MS/MS spectrum. Furthermore, the assignment of the substructures of the individual blocks acquired by MALDI-TOF MS/MS was accomplished with the help of the fragments that were obtained from the corresponding homopolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010