Preparation of CdTe quantum dots for detecting Cu(II) ions

Although copper is needed by the human body, excessive copper can cause diarrhea, vomiting, and neurological disorders. In this study, CdTe semiconductor quantum dots (QDs) with different emission wavelengths were fabricated and used for detection of copper ions. By controlling the temperature, nucleation and growth of the crystals in the aqueous phase were separated, which improved the optical properties of QDs. They were characterized with Fourier-transform infrared (FT-IR), Transmission electron microscope (TEM) and X-ray diffraction (XRD). After being coated by the sol-gel method, the QDs were used to detect Cu(II) ions. There was a good linear relationship between the concentration of Cu(II) ions and the quenching efficiency of fluorescent probes over the range 0-1 mg L-1, and the detection limit was 1.18 & mu;g L-1 (n = 10). Ratiometric fluorescent probes were also fabricated, which exhibited better Cu(II) ion detection, with a detection limit as 0.13 & mu;g L-1 (0.002 & mu;mol/L) that was far lower than the detection standard of copper ions in water.

Automated summary

In this study, CdTe semiconductor quantum dots (QDs) with different emission wavelengths were fabricated to detect copper ions. The nucleation and growth of crystals in the aqueous phase were separated by controlling the temperature, improving the optical properties of QDs. The QDs were coated using the sol-gel method for Cu(II) ion detection, and a good linear relationship between the concentration of Cu(II) ions and the quenching efficiency of fluorescent probes was observed. Ratiometric fluorescent probes were also fabricated, with a detection limit far lower than the standard for copper ion detection in water.