催化动力学光度法测定果汁中痕量硫脲含量  

Catalytic kinetic spectrophotometric determination of trace Thiourea in fruit juices

作　　者：蔡志刚[1] 金俏[1] 王园朝[1] 

机构地区：[1]杭州师范大学材料与化学化工学院,浙江杭州310036

出　　处：《化学研究与应用》2013年第11期1497-1501,共5页Chemical Research and Application

基　　金：杭州师范大学"本科生创新能力提升工程"实验室开放项目资助

摘　　要：在H2SO4介质及10℃温度下，硫脲能灵敏地催化碘酸钾与百里香酚蓝的氧化还原反应，由此建立了一种催化动力学光度法测定痕量硫脲的分析方法。探讨了催化反应的各种实验条件。在最佳实验条件下，非催化体系吸光度‰与催化体系吸光度A之比的对数lg（A0／A）与硫脲的浓度在2-700μg·L^-1范围呈现较好的线性关系，检出限为1．97μg·L^-1。该方法用于橘子和香橙实际样品中痕量硫脲的测定，三个加标水平的平均加标回收率分别为92．7％和103．8％，5次平行测定的相对标准偏差分别在1．18～4．32％和3．10—4．41％范围。A kinetic spectrophotometric method for the determination of trace levels of thiourea（TU）is established, based on its catalytic effect on the oxidation of thymol blue（TB） by potassium iodate in sulfuric acid media- The reaction was monitored by measuring the decrease in absorbance of TB at 547 nm. The effect of different parameters such as concentration of reactants and temperature on the rate of reaction was investigated, and optimum conditions were obtained. The calibration curve was linear in the concentration range 2-700μg·L^-1 of TU, and detection limit of the method was 1.97μg·L^-1. Most of foreign species do not interfere with the determination. The method was found to be sensitive, selective and was applied to the determination of TU in the juice of tangerine and orange with the average recovery ratio between 93.2 - 108.2%.

关 键 词：催化动力学光度法 百里香酚蓝 碘酸钾 硫脲 果汁 

分 类 号：O657.3[理学—分析化学]