摘要
通过对H_2O_2氧化4,5-二溴荧光素褪色反应的研究,发现在pH 5.0的HAc-NaAc缓冲溶液介质中,Cr(Ⅵ)对H_2O_2氧化4,5-二溴荧光素的褪色反应具有催化作用,据此建立了催化动力学光度法测定痕量Cr(Ⅵ)的新方法。讨论了酸度、反应物浓度、反应温度、反应时间、干扰离子等因素的影响,找出了反应的最佳条件,并测定了一些该反应的动力学参数。其反应的表观活化能为55.06 kJ/mol,表观速率常数k=2.05×10^(-3)/s。方法检出限为6.304×10^(-7)μg/mL,线性范围为0.004 4～0.3μg/mL。用于水样中痕量Cr(Ⅵ)的测定,其RSD为0.92%,加标回收率在96%～103%之间。
The oxidation reaction of 4,5-dibromofluorescein with hydrogen peroxide （H2O2） in HAc-NaAc buffer solution（pH 5.0）have been developed. It has been found that the Cr（Ⅵ） can catalyze the reaction. Based on these facts, a new method of catalytic kinetic spectrophotometric determination of trace Cr（Ⅵ） have been established. The influences of acidity, concentration of reacting substance, reaction temperature,reaction time etc. on the reaction have been discussed and the optimum reaction condition has been found. The apparent activation energy of the catalytic reaction, the apparent rate constant,the detection limit of the method and the linear range are 55.06 kJ/mol,2.05 × 10^-3/S,6. 304× 10 ^-7 μg/mL and 0. 004 4-0.3 μg/mL, respectively. The new method is convenient, quick-speed, high sensitivity and good selectivity. It has been applied to the determination of trace Cr（Ⅵ） in water sample with RSD of 0. 92% and recovery of 96%-103%.
出处
《冶金分析》
CAS
CSCD
北大核心
2007年第6期55-57,共3页
Metallurgical Analysis
