Nakamura Sayaka, Sato Hiroaki, N J Fouquet Thierry
Polymer Chemistry Group, Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
Mass Spectrom (Tokyo). 2020;9(1):A0079. doi: 10.5702/massspectrometry.A0079. Epub 2020 Feb 6.
The Kendrick analysis is used for the processing and visualization of mass spectra obtained from polymers containing C, H, O and/or Si with simple isotopic patterns (monoisotope=lightest isotope=most intense isotope for short chains). In the case of heteroatoms with complex isotopic patterns, the impact of the chosen isotope on point alignments in Kendrick plots has not been examined extensively. Rich isotopic patterns also make the evaluation of the mass and nature of the repeating unit and end-groups more difficult from the mass spectrum in the case of unknown samples due to the number of peaks and the absence of a monoisotopic peak. Using a polybrominated polycarbonate as running example, we report that horizontal point alignments can be obtained in a Kendrick plot using the mass of the most abundant isotope instead of the monoisotopic mass as is usually done. Rotating the plot ("reverse Kendrick analysis") helps to accurately evaluate the mass of the most abundant isotope of the repeating unit, as well as the nature of the brominated neutral expelled upon gentle heating (debromination or dehydrobromination). The whole procedure is then applied to the characterization of an unknown polybrominated flame retardant in an industrial formulation before and after heating.
肯德里克分析用于处理和可视化从含有碳、氢、氧和/或硅且具有简单同位素模式（对于短链，单同位素=最轻同位素=最强同位素）的聚合物获得的质谱。对于具有复杂同位素模式的杂原子，所选同位素对肯德里克图中点对齐的影响尚未得到广泛研究。丰富的同位素模式也使得在未知样品的情况下，由于峰的数量以及不存在单同位素峰，从质谱中评估重复单元和端基的质量和性质更加困难。以一种多溴化聚碳酸酯为例，我们报告在肯德里克图中可以使用最丰富同位素的质量而非通常使用的单同位素质量来获得水平点对齐。旋转该图（“反向肯德里克分析”）有助于准确评估重复单元最丰富同位素的质量，以及温和加热时（脱溴或脱溴化氢）排出的溴化中性物质的性质。然后将整个过程应用于工业配方中加热前后未知多溴化阻燃剂的表征。
