摘要
采用高效液相色谱-紫外检测法(HPLC-UV),分别以水杨酸(SA)和4-羟基苯甲酸(4-HBA)为捕捉剂,测定了电化学氧化体系中生成的·OH。使用紫外分光光度计确定不同捕捉剂的检测波长,通过条件控制的重复实验,系统研究了不同捕捉剂的捕捉能力,重点考察了不同捕捉剂初始用量及pH值对研究体系中·OH捕捉量的影响。研究结果表明,SA和4-HBA分别与·OH的电化学氧化反应均符合一级反应动力学,反应速率常数k分别为2.1833×10-4 s-1和1.3500×10-4 s-1。经过3次重复实验发现,达到相同的·OH捕捉量时,4-HBA所需的初始用量为SA的3倍,捕捉时间约为SA的2.3倍。通过对比研究发现,SA在UV检测条件下具有更高的灵敏度和更强的捕捉能力。
High performance liquid chromatography（HPLC）with ultraviolet detection（UV）was employed to determine the amount of hydroxyl radicals by using salicylic acid（SA）or 4-hydroxybenzoic acid（4-HBA）as a probe in electrochemical oxidation reaction system.The ultraviolet spectrophotometer was used to identify the detection wavelengths of species.From the repeated tests under controlled conditions,the effects of some important factors,such as the trapping efficiency of different selected probes and the initial concentration of probes,were investigated.The concentration of hydroxyl radicals in the reaction system was also detected to show the effects of reaction pH value.The results showed that the electrochemical reaction of SA or 4-HBA with hydroxyl radicals fitted the first-order kinetics and the relative rate constant was 2.1833×10-4s-1 and 1.3500×10-4s-1,respectively.To reach the same capacity of trapping,the initial concentration of 4-HBA was three times as SA,and electrolysis time was two times as SA which was proved by 3times of repeated experiments.From the comparison tests,SA was chosen as the optimum probe which had higher sensitivity and trapping efficiency under the HPLC-UV condition.
出处
《分析科学学报》
CAS
CSCD
北大核心
2015年第5期606-610,共5页
Journal of Analytical Science
基金
国家自然科学基金(No.51278407
51408468
51478379)
陕西省教育厅项目(No.13JS062
14JK1434)
