流动注射-循环催化法同时测定过氧化物酶活性和抗坏血酸浓度

Simultaneous determination of peroxidase activity and ascorbate concentration by flow-injection recirculating-catalysis system

利用一种流动注射-循环催化光度系统评价抗坏血酸(AsA)干扰过氧化物酶(POD)的催化反应机制,发现AsA会导致POD催化的显色产物褪色,使显色反应体系出现一种无响应的延滞期,当AsA消耗完后POD的催化动力学曲线线性响应区斜率及截距分别与POD活性和AsA浓度相关。基于此现象,建立了一种同时测定POD活性和AsA浓度的新方法。在优化条件下,该法成功用于多种萝卜中POD活性和AsA浓度的测定。方法的线性范围分别是50~2000 U/L POD和20~350 mg/L AsA,相对标准偏差小于1.4%。

A flow-injection recirculating-catalysis system was used to evaluate ascorbate(AsA)interference with the catalytic reaction mechanism of peroxidase(POD),showing that AsA can cause the chromogenic products catalyzed by POD to fade and result in a lag phase by the catalytic reaction of POD.When AsA was consumed,the slope and intercept of the linear response region was related to POD activity and AsA concentration,respectively.Based on this phenomenon,a new method was established for determining POD activity and AsA concentration simultaneously,which was successfully applied to the determination of POD and AsA in various radishes under optimized conditions.Quantification ranges of the method were 50-2000 U/L for POD and 20-350 mg/L for AsA,respectively,and the relative standard deviations were less than 1.4%.