萃取催化动力学光度法测定痕量铜

Determination of trace Copper by Extraction Catalytic Kinetic Spoctrophotometry

在ｐＨ＝９．８的氨性缓冲溶液中，痕量Ｃｕ（Ⅱ）对Ｈ２Ｏ２氧化邻氨基酚的显色反应有催化作用，用萃取平衡控制反应时间和水相中邻氨基酸的浓度及反应程度．研究了反应的最优条件，建立了测定痕量铜的新方法。方法的线性范围为０．５—２０μｇ·Ｌ（－１），检测限为２．２×１０（－７）ｇ·Ｌ（－１）。用本法测定了水及食品中的痕量铜，结果满意。

A new extraction catalytic kinetic spectrophotometric method for the determcnation of trace copperis studied. The method is based on the copper catalyzed oxidation of 0-aminophenol by hydrogen peroxide inweak acidic medium at PH 9. 8 The raction time. Concentration of o-aminophenol in agueous phase and degree of reaction are controued by extraction equilibrium. The absorbance of organic phase is measured at420nm. The linear range of the determination is 0. 50- 20g/L. The detection limit is 2. 2 ×10-7g/L. Themethod has been apptied to the determination of trace copper in water and food samples with satisfactory results.