二溴羟基苯基荧光酮荧光熄灭法测定痕量铬(Ⅵ)

A Fluorescence Quenching Method for the Determination of Cr(Ⅵ)with 2,3,7-Trihydroxy-9-Dibromo-Hydroxyphenylfluorone(DBH-PF)and Cetyltrimethylammonium Bromide

本文用荧光熄灭法研究了二溴羟基苯基荧光酮(DBH-PF)-溴化十六烷基三甲铵(CT-MAB)-Cr(Ⅵ))体系的测定方法及条件。在pH=2.4～3.4的盐酸介质中,在CTMAB存在下,Cr(Ⅵ)与DBH-PF形成1:2的配合物。该体系存在两个激发峰,其激发波长分别为(?)=470nm,(?)=502nm,发射波长(?)=520nm。铬浓度在0.04～0.40ug/25mL范围内,(?)与铬浓度呈现良好的线性关系,相关系数γ=0.9992,检测限为0.04ug/25mL。本法用于检测水样中的痕量铬,结果满意。在水样中加入0.20ugCr(Ⅵ),测得回收率在95%～105%之间。

Cr(Ⅵ)in water was rapidly determined by fluor- ometric quenching method using 2,3,7-trihydroxy-9- dibrom o-hydroxyphenyl fluorone(DBH-PF)and cetyltrimethylammonium bromide(CTMAB)as reagents. In HCI medium,Cr(Ⅵ),DBH-PF and CTMAB react to form a complex,Its Composition was established by meth- ods of isomolar continuous variation and equilibrium shift as Cr(Ⅵ):DBH-PF=1:2,its maximum excitation wavelengths are 470nm and 502nm,the maximum,emis- sion wavelength is 520nm.The linear range is 0.04～ 0.4μg/25mL,the detection limit of Cr(Ⅵ)is 0.04μg/ 25mL.This method is selective and highly sensitive to Cr (Ⅵ).Up to 3000 times of Ca(Ⅱ),Mg(Ⅱ),1000 time of Al(Ⅱ),Cu(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Mn(Ⅱ),Zn(Ⅱ), Ca(Ⅱ)and 125 times of Fe(Ⅱ)did not interfere,when 2mL 0.20% EDTA and 0.50mL 10% citric acid were used,60 times of W(Ⅵ),25 times of V(Ⅴ),2.5 times of Sn(Ⅵ),1 time of Mo(Ⅵ) did not interfere in the de- termination of 0.40μg Cr(Ⅵ).