摘要
基于光度滴定方法原理，在山奈酚与DPPH·反应的UV—Vis光谱研究基础上，提出了一种评估DPPH·清除活性的微量光度滴定新方法。测定了山奈酚与DPPH·反应的微量光度滴定曲线，提出以DPPH消耗量（nD）及山奈酚加入量（nK）化学计量数比（nD／nK）评价DPPH·清除能力、以及最大清除率（ECmax）和半数清除浓度（EC50）的计算方法。对于不同DPPH初始量，测得nD／nK在1．70～1．78之间，EC～和EC50值分别为84．32％和1．99×10^-2mmol·L^-1（相当于7．1×100^-7mol初始DPPH），均与常规方法结果相近，而本法具有更好的精密度，样品使用量明显下降。
A novel trace photometric titration method for the evaluation of DPPH radical scavenging activity was proposed based on the UV-Vis spectroscopic research of the reaction of kaempferol with DPPH radical.The titration curve of kaempferol with DPPH radical was tested. The methods for the evaluation of DPPH radical scavenging capacity, and for calculation of rfiaximal scavenging rate（ECmax） and median scavenging concentration （EC50）were proposed based on the stoichiometric ratio （nJnK）of DPPH consumption （no）to the addition of kaempferol （nK）.For different initial amounts of DPPH radical,the value of nD/nK was from ].70 to 1.78 with an ECmax, value of 84.32% and an ECso value of 1.99 ×10^-2mmol. L-1 （according to a DPPH radical initial amount of 7.1 ×10^-7 mol） ,the results above were agreement well with that of conventional method,while, better precision was achieved by using the proposed method with significant decrease in the amount of sample used.
出处
《食品工业科技》
CAS
CSCD
北大核心
2014年第5期53-57,共5页
Science and Technology of Food Industry
基金
国家自然科学基金项目(21205104)
云南民族大学绿色化学与功能材料研究省创新团队(2011HC008)
云南省高校科技创新团队支持计划资助(2011UYN09)
