水中痕量镉(Ⅱ)的荧光素-曙红Y能量转移荧光猝灭测定法

Determination of trace cadmium in water by energy transfer synchronous fluorescence quenching with fluorescein-eosine Y

目的建立水中痕量镉（Ⅱ）的荧光素-曙红Y能量转移荧光猝灭测定法。方法取0.50ml的水样置于5.0 ml的比色管中,分别加入1×10^-4mol/L荧光素溶液0.30 ml,1×10^-5mol/L曙红Y溶液0.10 ml,BR缓冲液（pH 6.5）0.50 ml,定容后在502 nm处测定溶液荧光强度（F）值,以内标法定量。结果在3.43×10-71.246×10^-5 mol/L的线性范围为,该方法所得镉（Ⅱ）的线性回归方程为ΔF=14.221＋546.81×10-5c,r=0.999 5。该方法的检出限为1.03×10^-8 mol/L,平均回收率为94.53%-98.15%,RSD为2.44%-4.67%。结论该方法操作简便、灵敏、选择性好,适用于水中镉（Ⅱ）的测定。

Objective To develop a novel energy transfer fluorescence quenching method for the determination of cadmium using fluorescein-eosine Y. Methods A total of 0.50 ml water sample, 1×10^-4 mol/L fluorescein solution 0.30 ml, 1 ×10^-5 mol/L eosin Y solution 0.10 ml and BR buffer （pH 6.5） 0.50 ml were added into 5 ml eolorimetric tube, then the fluorescence intensity was determined at 502 nm after constant volume. Results Under the optimal experimental conditions,there was a linear relationship between fluorescence intensity and the concentration of cadmium in the range of 0.344×10^-6 1.246×10^-5 mol/L at 502 nm.The linear regression equation was AF=14.221＋546.81×10^-5c （r=0.999 5）,the limit of detection was 1.03×10^-8 mol/L. The relative standard deviation were 2.44%-4.67% ,and the average recovery were 94.53%-98.15%. Conclusion The proposed method is simple, sensitive and selective, and suitable for the determination of trace cadmium in water samples.