荧光猝灭法测定痕量铬(Ⅵ)的研究

Studies on Fluorescence Quenching M ethod for the Determination of Trace Chromium(Ⅵ)

报道了以荧光素为指示剂,荧光法间接测定痕量Cr(Ⅵ)的新方法.在pH6.7～7.5中性缓冲介质中,I-与荧光素反应,使荧光素的荧光猝灭,当加入Cr(Ⅵ)时,Cr(Ⅵ)与I-反应使体系荧光增强.体系的激发和发射波长分别为490nm和515nm,测定Cr(Ⅵ)的线性范围为6.0～80μg·L-1,回归方程ΔF=0.26+1.02C(μg·L-1),相关系数r=0.9987,检出限为2.6μg·L-1.方法简便、灵敏度高,用于环境水样中痕量Cr(Ⅵ)的测定,并进行了加标回收试验,回收率在96%～103%之间.

A simple and sensitive fluorescence quenching method has been developed for the determination of trace chromium(Ⅵ)with fluorescein as the fluorogenic reagent (λ ex =490nm,λ em =515nm.)at pH 6.7-7.5.In a neutral medium,I - reacts with fluorescein resulting i n fluorescence decreasing.If chrom ium(Ⅵ)are present,the fluorescence intensity of the solut ion increases with the increasing co ncentration of chromium(Ⅵ).The linear range of determination is 6.0～80μg·L -1 ,and the linear regression equation isΔF=0.26+1.02C,and the correlative coefficient is r=0.9987,and the detection limit is 2.6μg·L -1 .The method was used to determination of trace chromium(Ⅵ)in environmental water samples,and recoveries in the range of 96%～103%are obtained.