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在pH 5.0的HAc-NaAc缓冲介质中,用2,2’-联吡啶作活化剂,Cu(Ⅱ)对抗坏血酸还原7-(2,6二-氯苯偶氮)-8-羟基喹啉-5-磺酸具有强烈催化作用且使体系的荧光显著增强,据此建立了催化动力学荧光光度法测定痕量铜的新方法。建立了反应动力学方程,确定此反应对试剂和铜均为一级反应,测得反应速率为2.36×10-6mol.L-1.min-1,求得表观活化能为72.86 kJ/mol。以341 nm为激发波长,443 nm为发射波长,其荧光增强强度与铜量在0.04~7.2μg/L范围呈线性关系,检出限为4×10-8g/L。采用巯基棉富集分离,用于钢样及铝合金中微量铜的测定,相对标准偏差为3.80%~4.40%;与认定值比较,结果相吻合。
In the HAc-NaAc buffer medium at pH 5.0, 2,2’-dipyridyl was used as activating agent, Cu (Ⅱ) was used to reduce the amount of 7- (2,6-chlorophenylazo) -8- 5-sulfonic acid has a strong catalytic effect and the fluorescence of the system was significantly enhanced. A new method for the determination of trace copper by catalytic kinetic fluorimetry was established. The reaction kinetic equation was established, and the reaction was confirmed to be a first-order reaction between the reagent and copper. The reaction rate was 2.36 × 10-6mol.L-1.min-1, and the apparent activation energy was 72.86kJ / mol . With the excitation wavelength of 341 nm and the emission wavelength of 443 nm, the fluorescence enhancement intensity showed a linear relationship with the amount of copper in the range of 0.04-7.2 μg / L with a detection limit of 4 × 10-8 g / L. The enrichment and separation by using sulfhydryl cotton was used for the determination of trace copper in steel samples and aluminum alloys with relative standard deviation of 3.80% -4.40%. The results were in good agreement with the certified values.