A novel, simple and convenient method for the determination of hydroxyl radicals isestablished. Hydroxyl radicals produced by Fenton reaction is trapped by spin trap reagent phenyl-t-butyl nitrone (PBN), and the free ...A novel, simple and convenient method for the determination of hydroxyl radicals isestablished. Hydroxyl radicals produced by Fenton reaction is trapped by spin trap reagent phenyl-t-butyl nitrone (PBN), and the free radical adduct of PBN can be detected by single sweeposcillopolarography, with its second order derivative cathodic wave at -0.52V vs SCE. Theoptimum experimental conditions for the detemination is discussed, and the scavenging effects ofsome compounds on OH was also studied.展开更多
通过单因素试验和正交试验探讨了Fe S0_4溶液用量、水杨酸-乙醇溶液用量、H_20_2溶液浓度、反应温度、反应时间对Fenton反应体系的影响,筛选出羟自由基反应体系的最优反应条件,并检测了乙醇体积分数、p H对反应体系的影响。结果表明,最...通过单因素试验和正交试验探讨了Fe S0_4溶液用量、水杨酸-乙醇溶液用量、H_20_2溶液浓度、反应温度、反应时间对Fenton反应体系的影响,筛选出羟自由基反应体系的最优反应条件,并检测了乙醇体积分数、p H对反应体系的影响。结果表明,最佳反应条件为1.8 mmol/L的Fe S0_4溶液2.50 m L,1.8 mmol/L的水杨酸-乙醇溶液2.00 m L,0.05%H_20_2溶液0.10 m L,蒸馏水0.50 m L,20℃水浴10 min。反应体系的p H及待测液乙醇体积分数对反应体系有明显影响,建议待测液含乙醇时,应做相同体积分数乙醇对照组进行修正。展开更多
The content of flavones of the seabuckthorn ( Hippophae rhamnoides L. )root bark,branch bark and leaves were determined using UV vis spectrophotometry.In the meantime,the scavenging hydroxyl free radical(OH ·)and...The content of flavones of the seabuckthorn ( Hippophae rhamnoides L. )root bark,branch bark and leaves were determined using UV vis spectrophotometry.In the meantime,the scavenging hydroxyl free radical(OH ·)and superoxide anion free radical(O 2 ·- )of the extracts of seabuckthorn root bark,branch bark and leaves were measured through Fenton reaction and pyrogallol autoxidation method.The results showed that the seabuckthorn root bark,branch bark and leaves had a strong capacity on scavenging free radical.The scavenging rates of hydroxyl free radical were 69.2%,62.2% and 74.1%,respectively.The inhibition rates of superoxide anion free radical were 10.5%,12.3% and 33.3%,respectively.Finally the antioxidant mechanism of seabuckthorn flavones were tentatively explored.展开更多
文摘A novel, simple and convenient method for the determination of hydroxyl radicals isestablished. Hydroxyl radicals produced by Fenton reaction is trapped by spin trap reagent phenyl-t-butyl nitrone (PBN), and the free radical adduct of PBN can be detected by single sweeposcillopolarography, with its second order derivative cathodic wave at -0.52V vs SCE. Theoptimum experimental conditions for the detemination is discussed, and the scavenging effects ofsome compounds on OH was also studied.
文摘通过单因素试验和正交试验探讨了Fe S0_4溶液用量、水杨酸-乙醇溶液用量、H_20_2溶液浓度、反应温度、反应时间对Fenton反应体系的影响,筛选出羟自由基反应体系的最优反应条件,并检测了乙醇体积分数、p H对反应体系的影响。结果表明,最佳反应条件为1.8 mmol/L的Fe S0_4溶液2.50 m L,1.8 mmol/L的水杨酸-乙醇溶液2.00 m L,0.05%H_20_2溶液0.10 m L,蒸馏水0.50 m L,20℃水浴10 min。反应体系的p H及待测液乙醇体积分数对反应体系有明显影响,建议待测液含乙醇时,应做相同体积分数乙醇对照组进行修正。
文摘以Fe Cl_3·6H_2O和Fe SO_4·7H_2O为原料,氢氧化钠溶液为沉淀剂,制备了磁性Fe_3O_4粒子。采用XRD、SEM方法表征,并研究了Fe_3O_4粒子对亚甲基蓝的降解作用。结果表明,Fe_3O_4粒子平均粒径为5μm,以Fe_3O_4-H_2O_2组成类Fenton反应体系降解10 mg/L的亚甲基蓝溶液,当溶液p H值为3,浓度3%的H_2O_2用量为4 m L和0.2 g Fe_3O_4粉末,9 h内亚甲基蓝的降解率可达98.69%。
文摘The content of flavones of the seabuckthorn ( Hippophae rhamnoides L. )root bark,branch bark and leaves were determined using UV vis spectrophotometry.In the meantime,the scavenging hydroxyl free radical(OH ·)and superoxide anion free radical(O 2 ·- )of the extracts of seabuckthorn root bark,branch bark and leaves were measured through Fenton reaction and pyrogallol autoxidation method.The results showed that the seabuckthorn root bark,branch bark and leaves had a strong capacity on scavenging free radical.The scavenging rates of hydroxyl free radical were 69.2%,62.2% and 74.1%,respectively.The inhibition rates of superoxide anion free radical were 10.5%,12.3% and 33.3%,respectively.Finally the antioxidant mechanism of seabuckthorn flavones were tentatively explored.
