水中痕量镉的曙红Y-中性红能量转移荧光猝灭法测定

在pH 7.9的BR缓冲液中,曙红Y-中性红和镉离子相互作用,在535 nm处荧光强度随着镉浓度的增加,体系的荧光逐渐降低,其荧光强度降低值和镉离子含量在一定范围内有相关关系.据此建立了一种测定痕量镉的曙红Y-中性红体系能量转移荧光猝灭新方法,并优化了实验条件.在优化的实验条件下,体系在535 nm处的荧光强度降低值与镉的摩尔浓度在1.6＆#215;10-8~3.2＆#215;10-6 mol/L范围内线性关系良好,其线性回归方程为：？F=936.60-2425.2c（＆#215;10-6mol/L）,相关系数r=0.998,检出限为4.7＆#215;10-9 mol/L,相对标准偏差是0.45%,加标回收率是90.75%.本方法操作简便、灵敏、选择性好,用于实际样品中镉的测定,其测定结果同石墨炉原子吸收法一致（t检验法）.

Determination of Trace Cadmium in Water with Eosine Y-Neutral Red by Energy Transfer Fluorescence Quenching Method

In the Britton-Robinson buffer solution of pH7. 9,the system intensity was obvi-ously decreased due to the interaction between the Eosine Y-Neutral red complex and cad-mium ion,and the decreased fluorescence intensity was proportional to the concentration of cadmium ion. Based on this phenomenon,a novel energy transfer fluorescence quenching method for the determination of trace cadmium with EosineY-Neutral red was proposed.And this paper optimized experiment conditions. Under the optimal experimental conditions,there was a linear relationship between the decreased fluorescence intensity and the concentration of the cadmium at 535 nm in the range of 1. 6＆#215;10 -8 ~3. 2＆#215;10 -6 mol/ L, The linear regression equation was ？F =936. 60 -2425. 2c（＆#215;10 -6mol/ L） with a correlation coefficient 0. 998,the detection limit was 4. 7＆#215;10 -9 mol/ L. The relative standard deviation was 0. 45% （n =6）,and the average recovery was 90. 75%. The proposed method is simple,sensitive and selective,and has been used successfully in the determination of trace cadmium in water samples,which results were in good agreement with those gained by graphite furnace atomic absorption spectrometry （GFAAS） method.