在pH 8.4的溶液中,碳量子点(Carbon quantum dots,CQDs)和荧光桃红(Fluorescent pink,FP)之间发生荧光共振而使后者的荧光增强。体系中加入痕量Cu^2+后,FP的荧光被猝灭,且在一定范围内体系的荧光猝灭程度与Cu^2+浓度呈良好的线性关系。据此建立了荧光猝灭法测定河水、农田水、自来水中痕量Cu^2+的新方法。方法的线性范围为9.42-23.55μmol/L,检出限(3σ/k)为3.14μmol/L。将该方法应用于河水、农田水及自来水中Cu2+的检测,其相对标准偏差(RSD)不大于0.91%,加标回收率为98.7%-99.0%,结果令人满意。
A new fluorescence method for the determination of trace Cu^2 +was developed by using fluorescence resonance energy transfer between carbon quantum dots and fluorescent pink,in which carbon dots acted as an energy donor and FP as an acceptor. It was found that under the conditions of λex= 581 nm and p H = 8. 4 aqueous solution,energy transfered from carbon dots to FP and led to enhance the fluorescence of FP. However,the addition of trace Cu^2 + made FP fluorescence quenching.The quenching degree was quantitatively in proportion to the trace Cu^2 +content. Therefore,a novel fluorescence quenching platform for determination of trace Cu^2 +was constructed. Under the optimum conditions,the calibration curve for Cu^2 +concentration was linear in the range of 9. 42- 23. 55μmol /L with a detection limit( 3σ /k) of 3. 14 μmol /L. The method was applied in the determination of trace Cu^2 +in river,farmland water and tap water,with spiked recoveries of 98. 7%- 99. 0%and relative standard deviations( RSD) not more than 0. 91%.