3-(4′-氯基苯基)-5-(2′-羧基偶氮)若丹宁催化动力学荧光光度法测定痕量锰

Catalytic-Kinetic Fluorophotometric Determination of Trace Amounts of Manganese(Ⅱ) with the Reagent 3-(4′-Chlorophenyl)-5-(2′-Carboxylphenylazo)-Rhodanine

研究发现在pH 5.2的邻苯二甲酸氢钾一氢氧化钠缓冲溶液中,Mn(Ⅱ)对过氧化氢氧化3-(4′-氯基苯基)-5-(2′-羧基偶氮)若丹宁的反应具有强烈的催化作用,并导致荧光强度的增加。据此建立了催化动力学荧光光度法测定痕量锰的方法,荧光强度的增加(ΔF)与Mn(Ⅱ)的质量浓度在0.014mg·L^(-1)以内呈线性关系,其线性回归方程为ΔF=-4.47+1038.75C,相关系数为0.9886,检出限为1.78×10^(-6)g·L^(-1)。用于自来水和污水样品中痕量锰的测定,测得结果与原子吸收光谱法(AAS)的结果相符。分析结果的相对标准偏差(n=6)均小于2.5%,用标准加入法测得的回收率在95.6%～103.4%之间。

A catalytic kinetic fluorophotometric method for determination of trace amounts of manganese（ Ⅱ ） was proposed based on the catalytic effect of Mn（ Ⅱ ） on oxidation of the reagent mentioned in the title by H2O2 in a phthalate buffer medium of pH 5.2. The resulting increase in intensity of fluorescence （AF） was measured at the wavelengths （λex/λem） 308 nm/404 nm. Linear relationship between values of △F and concentration of Mn（ Ⅱ ） was obtained in the range within 0. 014 mg · L^-1 as shown by the linear regression equation △F=-4. 47＋1 038. 75 C, where C is the concn. of Mn（ Ⅱ ） in 10 mL of solution （r=0. 988 6）. Detection limit of the method was found to be 1.78×10^-6g · L^-1. The proposed method was applied to analysis of samples of tap water and sewage, giving results in consistency with the results obtained by AAS. Values of RSD＇s （n = 6） calculated from the analytical results were less than 2. 5%. Test for recovery was made by standard addition method, and the results obtained were in the range of 95. 6%-103. 4%.