萃取阻抑光度法间接测定痕量硫脲  

Indirect Determination of Trace Thiourea by Extraction Inhibition Spectrophotometry

作　　者：孙登明[1] 张振新[1] 龚永俊 王国成[1] 

机构地区：[1]淮北煤炭师范学院化学系,安徽淮北235000

出　　处：《分析测试学报》2005年第2期54-56,共3页Journal of Instrumental Analysis

基　　金：安徽省教育厅自然科学基金资助项目(2001KJ196; 2004KJ320);淮北市科技计划基金资助项目(040145)

摘　　要：研究了在pH 4.5的柠檬酸盐缓冲溶液介质中,利用硫脲对钒(Ⅴ)催化溴酸钾氧化邻氨基酚显色反应的阻抑作用,用萃取平衡控制反应时间和水相中邻氨基酚的浓度及反应程度,通过测量424 nm下有机相的吸光度,建立了萃取催化光度法测定痕量硫脲的新方法.在最佳实验条件下,测定硫脲的线性范围为0.020～1.20 μg/mL,检出限为1.4×10-8 g/mL.对1.00μg/mL硫脲进行11次平行测定的相对标准偏差为3.8%.用于水样中硫脲的测定,结果满意.A new extraction inhibition spectrophotometric method for the indirect determination of trace thiourea was developed.It was based on the inhibition effect of thiourea on the catalyzing of vanadium(Ⅴ)on the oxidation of o-aminophenol by potassium bromate in weak acidic medium at pH4.5.The reaction time,concentration of o- aminophenol in aqueous phase and degree of reaction were controlled by extraction equilibrium.The absorbance of organic phase was measured at424nm.Under the optimum conditions,the linear range of the calibration curve was0.020～1.20μg/mL.The detection limit was1.4×10 -8 g/mL and the relative standard deviation(n=11)was3.8%for1.00μg/mL thiourea.The method has been apˉplied to the determination of thiourea in water with satisfactory results.

关 键 词：萃取 阻抑光度法 硫脲 钒 邻氨基酚 

分 类 号：O657.32[理学—分析化学]