荧光猝灭法定量检测镉离子浓度的可行性研究

Feasibility study on quantitative detection of Cd^(2+) using fluorescence quenching method

目的应用荧光猝灭法研究镉离子(Cd2+)与人血清白蛋白(HSA)之间的结合特征及机理,确认荧光猝灭法定量检测镉离子浓度的可行性。方法采用荧光猝灭法测定4种温度(25℃、31℃、37℃、41℃)时、不同镉离子浓度下HSA的荧光猝灭情况,然后根据Stern-Volmer方程描述HSA的荧光强度与Cd2+的浓度、反应体系温度之间的作用规律以及作用参数,并推理Cd2+对HSA荧光的猝灭机理。结果固定HSA的浓度为1×10-5mol/L,Cd2+(浓度为0.67×10-3mol/L^4.67×10-3mol/L)对HSA的荧光猝灭程度随Cd2+浓度的增加而加大,并呈良好的线性关系(r≥0.999 00),而且在4种温度中,随着温度的增加,猝灭常数越来越小。结论 Cd2+对HSA荧光的猝灭机理为静态猝灭,且在一定条件下有规律地猝灭,所以可以运用荧光猝灭法定量检测镉离子的浓度。

Objective Use fluorescence quenching method to study the interaction and mechanism between Cd2 ＋and human serum albumin（ HSA）, validate the feasibility of quantitative detection of Cd2 ＋using fluorescence quenching method.Methods Detect the fluorescence intensity of HSA at four temperatures（ 25 ℃,31 ℃,37 ℃,41 ℃） and different Cd2 ＋concentrations,and then describe the interaction regularity and parameter among fluorescence intensity of HSA,Cd2 ＋concentration and reaction temperature by Stern- Volmer equation,so as to infer the the quenching mechanism of Cd2 ＋for fluorescence quenching. Results Fixed concentration of HSA was 1 × 10^-5mol / L,fluorescence quenching degree of HSA intensified with the increasing of Cd2 ＋concentration and presented good linear relationship（ r≥0. 999 00） while Cd^2＋concentrations increased from 0. 67 × 10^-3mol / L to 4. 67 × 10^-3mol / L. And in the four temperatures,the quenching constants decreased while temperature increased. Conclusion The mechanism reveals the fluorescence quenching of HSA by Cd^2＋is a static process,and has the linear relationship under the specified conditions,so we can quantitatively detect the content of Cd2 ＋using fluorescence quenching method.