Diphenylamine (DPAH) and its derivatives have been widely used as antioxidants. Its antioxidation behaviors are started with the formation of diphenylamino radical (DPA^•) by loss of hydrogen atom through reaction with oxygen or ozone. DPAH was oxidized by ozonation to produce DPA^• and DPA^• was directly detected using atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The influence of oxidation time on generation of DPA^• and consumption of DPAH was also investigated.

中文翻译：

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使用常压化学电离质谱法直接检测二苯胺氧化形成的二苯氨基自由基

二苯胺（DPAH）及其衍生物已被广泛用作抗氧化剂。其抗氧化行为始于与氧或臭氧反应失去氢原子形成二苯氨基自由基（DPA ^•）。DPAH 通过臭氧氧化生成 DPA ^•并使用大气压化学电离质谱 (APCI-MS) 直接检测DPA ^•。还研究了氧化时间对 DPA ^•生成和 DPAH 消耗的影响。