阻抑过氧化氢氧化钙羧酸钠褪色反应动力学光度法测定水中痕量铜

Kinetic spectrophotometric determination of trace copperⅡ in water based on the inhibitory effect on discoloring reaction of calconcarboxylic acid with hydrogen peroxide

研究了在盐酸介质中，Cu（Ⅱ）阻抑过氧化氢氧化钙羧酸钠褪色反应的适宜条件，建立了阻抑动力学光度法测定痕量铜的新方法。在25mL测定液中，0～3．0μg铜呈线性关系，检出限为2．41×10^-8g／mL。l000倍K^＋，Na^＋，NH4^＋没有干扰；Al^3＋，Fe^3＋允许量较低，加入氟化物之后。可允许5倍Fe^3＋和10倍Al^3＋存在，方法已用于饮用水及河水中铜的测定。

It is found that the discoloring reaction of calconcarboxylic acid with hydrogen peroxide is inhibited by trace amounts of copper（Ⅱ） in the medium of 0.1 mol/L HCl. Based on this, a new inhibitory kinetic spectrophotometric method for the determination of trace copper in water is presented. The maximum absorption wavelength of inhibitory system is located at 540 nm. The linear range of the determination is 0 - 3.0 μg/25 mL.The detection limit is 2.41 × 10^-8 g/mL.Common coexisting ions, except for FetID and Al（Ⅲ） do not interfere with the determination. By masking Fe（Ⅲ） and Al（Ⅲ） with NH4F, the proposed method has been applied to the determination of trace copper in water with RSD between 2.4 % and 3.3 % （n = 6）. The apparent activation energy for the inhibitory reaction is 50.53 kJ/mol.