Abstract:

In this study, highly-fluorescent and water-soluble CdTe quantum dots (QDs) were used as fluorescence probe
to quantitatively detect Cu2+ in preserved egg samples. Using thioglycollic acid (TGA) and thioglycerol (TGOL) as the
stabilizers, the CdTe QDs were synthesized in water phase. The luminescent characteristics of CdTe QDs were studied
using UV-visible spectrophotometry and fluorescence spectroscopy. This experiment investigated the mechanism of the
fluorescence quenching effect of Cu2+ on CdTe QDs and based on the quenching effect, a method for detecting trace Cu2+
using QDs as a probe was established. The results showed the relationship between Cu2+ concentration in the range from 10
to 200 nmol/L and the quenching intensity of CdTe QDs (F) was fairly linear with high correlation coefficient (R2 = 0.997).
The limit of detection was 0.96 nmol/L, and the developed method presented relatively high selectivity and sensitivity. This
method was successfully applied to the analysis of preserved egg samples. The precision, expressed as relative standard
deviation (RSD), was 1.47%–3.01%, and the recovery rate was between 104% and 108%.

Key words: quantum dots, fluorescence quenching, Cu2+, preserved egg