催化光度法测定水中痕量汞

Catalytic Photometric Determination of Trace Amounts of Mercury in Water

痕量汞的存在对在稀硝酸介质中亚铁氰化钾及1，10-二氮菲之间的反应有明显的催化作用，在508nm波长处测定催化体系及非催化体系的吸光度A及A0并计算其吸光度差△A，该体系的△A与相应汞的质量浓度从2．0×10^-3～6．4×10^-2mg·L^-1之间呈线性关系（r=0．9876），其摩尔吸光率为5．92×10^5L·mol^-1·cm^-1。对一件水样按此方法测定其汞含量，测得结果的RSD（n=6）值为0．134％。按标准加入法进行了回收率试验，所得结果在97．5％～102．7％之间。

It was found that the reaction between potassium ferrocyanide and 1, 10-phenanthroline was catalyzed by Hg（Ⅱ） ion in dil. HNO3 solution. Absorbance values of the catalyzed （A） and non-catalyzed （A0） reaction systems were taken at the wavelength 508 nm. Linear relationship between values of △A（A-A0） and concn, of Hg（Ⅱ） added to the reaction system was found in the range from 2. 0×10^-3 to 6.4 × 10^-2 mg·L^-1 （r=0. 987 6） with a molar absorptivity （ε508） of 5.92× 10^5L·mol^-1·cm^-1. The proposed method was applied to the determination of mercury in a water sample and the value of RSD （n=6） calculated from the analytical results was 0. 134%, values of recovery obtained in the recovery test were in the range of 97.5%-102. 7%.