Institut d'Electronique et de Télécommunication de Rennes (IETR UMR CNRS 6164), Université de Rennes 1, Campus de Beaulieu, 263 Avenue du General Leclerc, 35042 Rennes Cedex, France.
Anal Chem. 2012 Oct 16;84(20):8642-9. doi: 10.1021/ac301759q. Epub 2012 Oct 2.
Direct analysis in real time (DART) ionization method is used with a time-of-flight (TOF) mass spectrometer to perform the analysis of industrial polyethylene pellets free of additives or containing Irgafos 168 as stabilizing agent without any sampling step. The developed analytical method uses the M + H ion of the bis(2-ethylhexyl) phthalate (DEHP) for performing the exact mass measurements of the stabilizer and polymer ions using the mass drift compensation procedure available on the AccuTOF mass spectrometer. DEHP is in fact a plastic contaminant always presents on the mass spectra of the analyzed samples. The mass spectra allow one to characterize either the ions of the polyethylene and that of the Irgafos. The analysis of thermally treated samples show that the polymer does not undergo any degradation when the Irgafos is present in the bulk of the material, and the role played by the Irgafos 168 is that of an oxygen trapping agent. Under UV exposure, the DART-TOF MS analyses performed on the exposed polyethylene pellets shows that the Irgafos 168 behavior toward the UV radiations is different since this one reacts by cleavages of its P-O bonds to prevent the degradation of the polymer. These interpretations are supported by all the elemental formula determination of the detected ions.
直接实时分析 (DART) 电离法与飞行时间 (TOF) 质谱仪结合使用，无需任何采样步骤，即可对不含添加剂或含有 Irgafos 168 作为稳定剂的工业聚乙烯颗粒进行分析。所开发的分析方法使用邻苯二甲酸二（2-乙基己基）酯 (DEHP) 的 M + H 离子，使用 AccuTOF 质谱仪上可用的质量漂移补偿程序对稳定剂和聚合物离子进行精确质量测量。实际上，DEHP 是一种塑料污染物，总是存在于分析样品的质谱中。质谱允许对聚乙烯的离子和 Irgafos 的离子进行特征化。对热处理样品的分析表明，当 Irgafos 存在于材料的本体中时，聚合物不会发生任何降解，而 Irgafos 168 的作用是作为氧捕获剂。在紫外光照射下，对暴露的聚乙烯颗粒进行的 DART-TOF MS 分析表明，Irgafos 168 对紫外辐射的反应不同，因为它通过其 P-O 键的断裂来反应，以防止聚合物降解。这些解释得到了所有检测到离子的元素式确定的支持。
