By taking inspiration from the food industry, an assay was investigated as a potential screening tool to test the efficiency of new phenolic antioxidants. The method was based on the spectrophotometric measurement of the stable free radical 1,1-diphenyl-2-picryl hydrazyl (DPPH) which, in its radical form, has an absorbance maxima at 515 nm. The disappearance of this absorbance band, upon reaction with an antioxidant, was monitored to reveal the kinetic pathway of the reaction, which was defined simply as either fast, medium or slow. Adaptation of the assay was attempted for application to biofuels and oil-based automotive fluids whereby the effect of polar and non-polar solvents on the kinetics of the reaction was investigated. In addition, the stoichiometry of the radical scavenging reaction was also analysed to give an insight into the structure-activity relationships of phenolic antioxidants.

中文翻译：

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从食物到出行：使用稳定的自由基 DPPH 研究新型汽车抗氧化剂的筛选试验

通过从食品工业中汲取灵感，研究了一种检测方法，作为一种潜在的筛选工具，以测试新型酚类抗氧化剂的效率。该方法基于对稳定自由基 1,1-二苯基-2-苦基肼 (DPPH) 的分光光度测量，其自由基形式在 515 nm 处具有最大吸光度。在与抗氧化剂反应后，该吸收带的消失被监测以揭示反应的动力学途径，该反应简单地定义为快速、中速或慢速。尝试将该测定法应用于生物燃料和油基汽车流体，由此研究了极性和非极性溶剂对反应动力学的影响。此外，