二甲基亚砜捕获-高效液相色谱法测定羟基自由基

Determination of Hydroxyl Radicals by Dimethyl Sulfoxide Trapping-High Performance Liquid Chromatography

本文建立了一种简便灵敏的方法用于测定Fe(Ⅲ)催化的光反应产生的·OH。通过二甲基亚砜(DMSO)捕获·OH生成甲醛,再与衍生试剂2,4-二硝基苯肼(DNPH)反应生成相应的腙(HCHO-DNPH),并用高效液相色谱法进行分析测定。研究了衍生试剂浓度、pH、不同衍生温度和衍生时间对衍生化反应的影响,确定衍生试剂浓度为270μmol/L,pH=4,温度为50℃,时间为30 min的最佳衍生化条件。同时确定了色谱条件。在优化的实验条件下,甲醛在0.10~5 mg/L范围内与衍生物HCHO-DNPH峰面积线性关系良好,相关系数为0.9962,对·OH的检出限为0.0027 mmol/L,定量限为0.0090 mmol/L,平均回收率范围为102.41%~117.61%,相对标准偏差小于8%。采用该方法对Fe(Ⅲ)参与的光反应生成的·OH进行了测定,结果满意。

In this paper,a simple and sensitive method for the determination of hydroxyl radical(·OH)generated from Fe(Ⅲ)-catalytic photo reaction was established.The concentration of·OH in the reaction system was determined indirectly by high performance liquid chromatography(HPLC)coupled with trapping·OH by dimethyl sulfoxide(DMSO)to produce formaldehyde quantitatively,which reacted with 2,4-dinitrophenylhydrazine(DNPH)to generate corresponding hydrazine(HCHO-DNPH).The effects of derivatizing reagent concentration,pH,derivatization temperature and time were studied and the optimum conditions were as follows:270μmol/L derivatizing agent,pH 4,the reaction temperature of 50℃and rection time of 30 min.The HPLC conditions were investigated as well.Under the optimized experimental conditions,the linear correlation coefficient was 0.9962 in the range of 0.10-5.00 mg/L.The detection limit and quantification limit of the method were 0.0027 mmol/L and 0.0090 mmol/L,respectively.The average recoveries were in the range of 102.41%-117.61%with relative standard deviation less than 8%.The method had been adopted to determine·OH photogenerated in Fe(Ⅲ)-photo reaction.