Al(Ⅲ)-8-羟基喹啉-5-磺酸荧光猝灭法测定痕量氟离子

Spectrofluorimetic Determination of Trace Fluoride Based on Fluorescence Inhibition of Al(Ⅲ)-8-hydroxyquinoline-5-sulphonic Acid Complex by Fluoride

本文建立了利用Al(Ⅲ)-8-羟基喹啉-5-磺酸络合体系测定痕量F-的荧光猝灭分析方法。在pH=4.90的HAc-NaAc缓冲体系中,Al(Ⅲ)和8-羟基喹啉-5-磺酸能够形成稳定的有较强荧光的络合物,激发和发射波长分别为365nm和494.4nm。该体系中加入F-后络合物荧光不同程度猝灭,当F-浓度为0.2～3.5μg·mL-1时,其荧光猝灭程度与F-的浓度呈线性关系,方法加标回收率为96.2%～104.0%,相对标准偏差(RSD)小于3.5%,检测限为10ng·mL-1。用抗坏血酸-邻菲罗啉掩蔽可消除Fe(Ⅲ)、Cu(Ⅱ)和Ni(Ⅱ)的干扰。该方法简便快速、灵敏度高、选择性好,可用于水样和牙膏中氟化物的测定。

The addition of fluoride to the fluorescence system of AI（ Ⅲ ）-8-hydroxyquinoline-5-sulphonic acid complex（Al（ Ⅲ ）-HQS） （2ex=365 nm,2om=494.4 nm） in HAc-NaAe buffer（pH 4.90） solution leads to immediate fluorescence inhibition, which is proportional to the amount of fluoride. Based on this finding,a novel spectrofluorimetic method for the determination of fluoride has been developed. The linear calibration range was from 0.2 to 3.5 μg.mL-1 and the detection limit was 10 ngomL-1. Ascorbic acid and 1,10-phenanthroline were used to eliminate the interferences of Fe（ Ⅲ ）, Cu （ Ⅱ ） and Ni （ Ⅱ ）. The proposed method has the advantages of high selectivity, simplicity and rapidity and has been applied to the determination of fluoride in water and toothpaste with recoveries of 96.2%-104.0%. The results obtained from the certified reference material by the present method agreed with the certified values.