溶剂及pH值对1,1-二苯基-2-苦肼基自由基分析法的影响

Effects of Solvents and pH on DPPH· Assay

研究了水和多种有机溶剂以及pH值对1,1_二苯基_2_苦肼基自由基(DPPH·)分析法的影响。结果表明 ,所试溶剂对该测定体系的影响不大 ,通过扣除溶剂的影响后 ,同一种抗氧化剂在不同溶剂中的抗氧化活性相近 ,表明该分析体系可用于水及多种有机溶剂提取物抗氧化性质的研究。 pH值对该分析体系的影响较大 ,强酸、强碱使DPPH·溶液迅速失效 ,在

The effects of water, organic solvents and pH on the assay of 1,1 _ diphenyl _ 2 _ picrylhydrazyl free radical(DPP H·) is reported. The radical _ scavenging activities of an antioxidant in various solvents are similar after deducting the blank solvent effect. It implies that the effect of tested solvents is small. This method is useful for the evaluation of the antioxidant activity in water and many organic solvents. However, solution pH plays a crucial role in this assay. DPPH· radicals collapse rapidly in strong acidic and alkaline solutions. The antioxidant activity is reduced with an increase of pH in the range of pH 2～10.