基于β-环糊精对荧光桃红的荧光增敏作用的开关型荧光探针测定痕量镍

Determination of Trace Amount of Nickel with a Fluorescence “Switching” Probe Based on Enhancement of Fluorescence of Phloxine by β-Cyclodextrin

在pH 7.6的PBS介质中,且在PVA存在下,荧光桃红在其荧光发射峰555nm处的荧光强度因β-环糊精的加入而增强(荧光开),当在此体系中加入镍(Ⅱ)离子,其荧光发生猝灭(荧光关),其猝灭程度(ΔIf)与镍(Ⅱ)的质量浓度在5~300μg·L-1范围内呈线性关系,检出限(3S/N)为1.75μg·L-1。应用此'开关'型荧光探针测定了污水和矿石样品中镍的含量,并用标准加入法进行回收试验,测得回收率在98.8%~106%之间,测定值的相对标准偏差(n=10)在1.2%~2.2%之间。对此荧光体系的反应机理也作了初步探讨。

In a PBS medium of pH 7.6 and in the presence of PVA,the fluorescence intensity(If)of phloxine at its fluorescence emission maximum of 555nm was enhanced by addition ofβ-cyclodextrin(called'swtching in'),and was quenched by the presence of Ni(Ⅱ)ion(called'switching off'),and the magnitude of fluorescence quenching(ΔIf)was found to keep linear relationship with mass concentration of Ni(Ⅱ)in the range of 5-300μg·L-1,with detection limit(3S/N)of 1.75μg·L-1.This so-called fluorescence'switching'probe was used for fluorimetric determination of trace amount of Ni in waste water and ore samples,and recovery was tested by standard addition method,giving values of recovery and RSD′s(n=10)in the ranges of 98.8%-106% and 1.2%-2.2% respectively.A preliminary discussion on the mechanism of the fluorescence reaction system was also given.