本研究以DSC進行Cu2+/ H2O2閉密式系統過氧化氫與銅離子反應相容性研究,分別探討銅離子濃度、過氧化氫溶液濃度、溶液pH值、氯離子濃度、硫酸根離子濃度對過氧化氫及銅離子共存系統反應起始溫度及放熱量的影響,並配合DSC應用以瞭解自由基反應行為受添加劑種類及濃度之影響,以快速驗證抗自由基產品之幼纂A並作為開發新抗自由基產品之依據。配合理論模式瞭解Cu2+/ H2O2系統中自由銅離子及螯合銅離子成分分佈受溶液pH值,螯合劑種類及濃度變化之影響,用以說明對系統反應起始溫度之變化之影響。於較低溶液pH值下(pH=0.0、0.5)Cu2+/ H2O2/NTA系統,主要以自由銅離子形式存在,NTA的添加會與氫氧自由基形成低活性含NTA*自由基的中間產物,進而提高系統之反應起始溫度;於較高溶液pH值下(pH=1.5、2.0),Cu2+/ H2O2/NTA系統,主要以螯合銅離子形式存在,反應起始溫度隨螯合銅離子濃度增加而增加,進而提高系統的反應起始溫度;加上可能CuNTA-與氫氧自由基形成高活性含CuNTA-*自由基的中間產物,進而導致DSC的整體反應行為愈來愈集中,此現象與Cu2+/ H2O2/EDTA系統之反應行為相似。添加維生素C及葡萄籽萃取物則可能藉由形成低活性的中間產物,進而提高反應起始溫度,且整體反應沒有集中的現象。相同濃度的EDTA對反應起始溫度的提高效果遠高於相同濃度的維生素C,且整體反應行為有明顯差異,藉此可作為後續氫氧自由基抑制劑開發的依據。
The compatibility of hydrogen peroxide and copper ions was studied under various concentrations of copper ions, hydrogen peroxide, sulfate ions, chloride ions, additives and solution pH values by DSC analyzer. The thermal reaction behaviors analyzed by DSC for solutions of different pH at Cu2+/ H2O2/ chelating agent system varied significantly and can be explained by the species distribution of free metal ions and chelated metal ions in aqueous solutions. The onset (initial thermal reaction) temperature was found be increased obviously with increasing the chelated copper ions at higher solution pH values resulted from inhibiting the free radical generation at Cu2+/ H2O2/ chelating agent system. Addition of Vitamin C and grape seed extract will increase the onset temperature due to generate lower reactivity intermediate from reaction between free radicals and additives at Cu2+/ H2O2 system. Antioxidants might be developed with DSC analyzer by identifying the thermal reaction behaviors between free radicals and additives.