以卟啉吡啶季铵盐为显色剂分光光度法测定水中痕量铜

Spectrophotometric Determination of Trace Amounts of Copper in Water with Pyridyl Quaternary Ammonium Salt of Porphyrin as Colour Reagent

应用新试剂5-[4-N-(对氯)-苄铵基吡啶基]-10,15,20-三(4-N-吡啶基)卟吩氯化物作显色剂,用分光光度法测定了痕量铜,在pH 3.2的邻苯二甲酸盐缓冲介质中,此试剂与铜离子生成组成比为1比1的稳定配合物,其吸收峰位于428.0 nm波长处,表观摩尔吸光率为1.9×105L.mol-1.cm-1。铜含量在0.1 mg.L-1以内符合比耳定律,其线性回归方程为A=0.0152+0.31C(r=0.999 1)。按所提出的方法测定了3种环境水标准样品中的痕量铜(Ⅱ),测得结果与标准值相符。

A new chromogenic reagent, 5-[4-N-（p-chloro）-benzylammonium pyridyl]-10, 15,20-tris （4-N- pyridyl） porphyrin chloride, was use in the spectrophotometric determination of trace amounts of copper. In a phthalate troffer medium of pH 3. 2, a coordination complex was formed between the new porphrin reagent and Cu^2＋ ion with its absorption maximum at the wavelength of 428. 0 nm, and mole ratio of 1 to 1. Apparent molar absorptivity （ε428） was found to be 1.9× 10^5L· mol^-1 · cm^-1. Beer＇s law was kept within 0. 1 mg of Cu^2＋ in 1 L of solution, in respective to its linear regression equation of A=0. 0152＋0. 31 C （r=0. 999 1）. The proposed method was applied to the determination of trace amounts of copper in 3 standard samples of environmental water, giving results in consistencv with the standard values.