Detection of Cd(II) ions by a self-tuning method using quantum dot fluorescence sensing

In this report, a novel self-tuning method for the detection of Cd(II) ions via Cu,Mn:ZnSe quantum dot (QD) fluorescence (FL) sensing has been put forward. The detection limits of Cd(II) ions are 10 nmol l⁻¹ to 1.5 µ mol l⁻¹. The fluorescence characteristic of Cu,Mn: ZnSe QDs strongly depends on the temperature and pH value of the solution in which they are grown. QDs prepared with suitable FL characteristics can be used to determine the regular pattern relating the concentration of Cd(II) ions and the FL of Cu,Mn:ZnSe QDs by adding varying amounts of Cd(II) ions. What is innovative here is that not only the single value of the peak FL of impurities Cu or Mn, but also the ratio of two peak values of FL, is used to obtain a linear fitting. Via comparison of the results of single-value and ratio-based detection, self-tuning detection of Cd(II) ions is achievable. (paper)