锑的野外快速分析方法——锑-5-Br-PADAP光导比色法

Rapid Field Analytical Method of Antimony—Fibre-optic Spectrophotometric Determination of Antimony using 2-[(5-Bromo-2-Pyridyl)-Azo]-5-Diethyl-Aminophenol

详细考察了在野外实验条件下碘锑络合物与2[(5溴-2-吡啶)-偶氮]-5-二乙氨基苯酚(5-Br-PADAP)形成蓝色三元络合物的各种影响因素,制定了适合野外使用的测定锑的快速光导比色法.样品经王水封闭溶解后,用尿素除去残余的HNO3,在H2SO4介质中使碘锑络合物与5-Br-PADAP形成三元络合物,用自行开发研制的光导分光光度计进行比色测定.方法检出限(3s)为0.26 μg/g,加标回收率为96.4%～102.4%,11次测定的精密度(RSD)小于8.90%.方法经国家一级标准物质验证,分析结果与标准值吻合.

A rapid field fibre-optic spectrophotometric method for determination of antimony based on the chromatogenic reaction of antimony-iodine complex with 2- [ （ 5-bromo-2-pyridyl ） -azo ] - 5-diethyl-aminophenol （ 5-Br-PADAP） was developed and some factors affecting the antimony analysis were studied. The sample is digested with aqua regia and urea is added into the sample solution to eliminate influence of remanent nitric acid. Antimony, iodine and 5-Br-PADAP formed blue ternary complex in sulphuric acid medium. Absorbance of the ternary complex is determined with fibre-optic spectrophotometer designed by the author. The detection limit of method is 0.26 μg/g for Sb. The method has been applied to the determination of antimony in national standard reference samples and the results are in agreement with certified values with precision of less than 8.90% RSD （n = 11 ）. The recoveries of standard addition are 96.4% - 102.4%.