Zheng Huai-li, Long Teng-rui, Zhu Yan
Faculty of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2004 Jan;24(1):114-7.
A kinetic spectrophotometric method for the determination of trace Cu(II) was developed in this paper. This method is based on the discoloring oxidation reaction between malachite green and hydrogen peroxide catalyzed by copper(II) in the medium of HCl solution. The influential factors of reaction and the optimum conditions for the determination of Cu2+ were investigated in detail. The decrease in absorbance was measured at 615 nm at fixed time intervals. The linear determination range is between 0 and 22 microg x L(-1) of copper(II). A detection limit of 1.92 microg x L(-1) is achieved. The catalytic and non-catalytic reactions are the first-order on copper(II), in the reaction time interval 15-20 min at 70 degrees C. The apparent activation energy of the catalytic reaction is 122.3 kJ x mol(-1). The apparent rate is 7.70 x 10(-4) s(-1). The Relative Standard Deviations (RSD) are 1.16% and the recoveries are 98.3%-100.3%. By masking Fe(III) ion with PO4(3-), the method can be applied to the determination of copper in water sample and foodstuffs with satisfactory results.
本文建立了一种动力学分光光度法测定痕量铜（II）。该方法基于在盐酸溶液介质中，铜（II）催化孔雀石绿与过氧化氢之间的褪色氧化反应。详细研究了反应的影响因素及测定铜离子的最佳条件。在固定时间间隔下于615nm处测量吸光度的降低。铜（II）的线性测定范围为0至22μg·L⁻¹。检测限为1.92μg·L⁻¹。在70℃下反应时间间隔为15 - 20分钟时，催化反应和非催化反应对铜（II）均为一级反应。催化反应的表观活化能为122.3kJ·mol⁻¹。表观速率为7.70×10⁻⁴s⁻¹。相对标准偏差（RSD）为1.16%，回收率为98.3% - 100.3%。通过用PO₄³⁻掩蔽铁（III）离子，该方法可应用于水样和食品中铜的测定，结果令人满意。
