【摘要】 将超氧化钾(KO2)溶解于二甲基亚砜(DMSO)和十八冠醚混合溶剂中可以制备稳定的超氧阴离子自由基(O2-.)的溶液,在该溶液体系中O2-.与氯化硝基四氮唑蓝(nitroblue tetrazolium,NBT)可以定量反应生成蓝色的单甲臢(monoformazan),用分光光度法进行检测。研究证实:单甲臢在DMSO溶液中的最大吸收波长为680 nm;反应时间和反应温度对测定结果有一定的影响。NBT与O2-.反应5 min较为适宜;由于低温条件下O2-.较为稳定,故测定温度维持在20℃左右。反应后体系吸光度与O2-.量之间的线性方程为:A680=(-0.071±0.015)+(2.607±0.037)X,r=0.999 8,其中X为O2-.的量,标准偏差为1.4%。抗坏血酸对O2-.清除效果的验证实验表明,该方法可应用于实验室抗氧化剂的筛选与研究。更多还原

【Abstract】 Highly stable superoxide anion radical(O-2·) solution prepared by dissolving KO2 in dimethyl sulfoxide(DMSO) and 18-crown-6 ether could react with nitroblue tetrazolium to form a blue compound with a maximum absorbance wavelength at 680 nm.Spectrophotometric results showed that the optimum time and temperature for the reaction of O-2· and NBT was 5 min and 20 ℃,respectively,and that the relationship between monoformazan absorbance and O-2· concentration was linear with a correlation coefficient of 0.999 8.The standard deviation was 1.4%.It was found that ascorbic acid could eliminate O-2· effectively,thus the proposed method can also be used for the screening of antioxidants in the laboratory.更多还原