5-磺基水杨酸—Fe^(3+)荧光探针测定EDTA

Determination of EDTA Based on the Fluorescence Recovery of 5-sulfosalicylic Acid-Fe^(3+) Complex

5-磺基水杨酸是一种常用的铁指示剂,但关于其荧光性质的研究报道很少.通过研究5-磺基水杨酸与Fe3+相互作用的荧光光谱,发现Fe3+可以选择性猝灭5-磺基水杨酸的荧光,而EDTA的加入可以使5-磺基水杨酸-Fe3+配合物离解,荧光恢复.基于5-磺基水杨酸荧光的"关-开",建立了一种测定EDTA的荧光分析新方法.在优化的实验条件下,该方法的线性范围为1.0×10-6～1.2×10-5mol/L,检出限为6.0×10-7mol/L,对浓度为6.0×10-6mol/L的EDTA平行测定11次,相对标准偏差为3.1%.该方法成功用于测定水样中的EDTA.

A new spectrofluorimetric method was developed for determination of EDTA.The interaction between 5-sulfosalic acid and Fe^3＋ was studied by using UV-vis absorption and fluorescence spectras.It found that Fe3＋ could quench the fluorescence of 5-sulfosalicylic acid and the fluorescence of 5-sulfosal-icylic acid-Fe^3＋ recovered when EDTA was added.Under the optimum conditions,the dynamic range forthe determination of EDTA was 1.0×10^-6～1.2×10^-5mol/L,and the detection limit（3σ/k） was 6.0×10^-7mol/L.The relative standard deviation was 3.1% for the determination of 6.0×10^-6mol/L EDTA（n=11）.This method could be successfully applied to determination of EDTA in real water samples.