镧-3-茜素甲基胺一N,N-二乙酸荧光光度法测定水样中痕量氟离子的研究

Study on the Determination of Trace Fluoride Ions in Water by Spectrofluorophotometer Based on Aliazrin-3-Methylamine-N,N-Diacetic Acid-Lanthanum

3-茜素甲基胺-N,N-二乙酸(ALC)具有荧光性质,La^(3+)可与ALC生成二元络合物La-ALC而显著猝灭其荧光强度,但F-与La-ALC进一步形成三元络合物时会增强该二元络合物的荧光强度,基于此建立了水样中痕量F-的La-ALC荧光光度测定新方法。对试剂用量、pH值的影响和反应时间等实验参数进行了优化选择,考察了淡水中常见离子的干扰情况。在优化的实验条件下,方法的线性范围为0.050-0.600μg/mL,检出限为0.027μg/mL,分别对0.100和0.400μg/mL的标准溶液平行测定6次,相对标准偏差(RSD)分别为2.95%和1.99%。以自来水、河水和矿泉水等水样为基底,进行加标回收实验,加标回收率介于98%—111%之间。本法用于矿泉水样的测定,与GB 7483-87的测定结果无显著差异。

Aliazrin-3-methylamine-N,N-diacetic acid （ALC）-Lanthanum is a fluorescent, and the fluorescence intensity could be quenched by lanthanum ion by forming La-ALC complex, however, ternary complex formation with fluoride （La-ALC-F） would be enhanced fluorescence intensity of La-ALC complex. A novel spectrofluorophotometery for the determination of trace fluoride was established based on this fluorencence enhancement. Experimental parameters, including the reagent concentrations, the effect of pH and the reaction time, were optimized using a univariate experimental design. Under the optimized conditions, the linearity and the detection limit were found to be 0. 050 to 0. 600μg/mL and 0. 027μg/mL,respectively. The relative standard deviations （RSD） were 2. 95% and 1.99% for standard solutions with F concentrations of 0. 100 and 0. 400μg/mL, respectively. The recoveries ranged from 98% to 111% for the matrix of tapwater, river water or mineral water. Two mineral water samples were analyzed by the proposed method, which has no significant difference compared to the GB 7483-87 method.