Dual-channel optical sensing platform for detection of diminazene aceturate based on thioglycolic acid-wrapped cadmium telluride/cadmium sulfide quantum dots

We design a dual-channel optical sensing platform which combines the advantages of dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) and fluorescence for the detection of diminazene aceturate (DA). The proposed method has been applied successfully to the detection of DA in milk samples. [Display omitted] •A dual-channel optical sensing platform has been designed for the detection of DA.•The sensing platform combines the advantages of DWO-RRS and fluorescence.•The possible mechanism of the sensing system was also explored.•The proposed method has been successfully applied to the detection of DA in the milk samples. A dual-channel optical sensing platform which combines the advantages of dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) and fluorescence has been designed for the detection of diminazene aceturate (DA). It is based on the use of thioglycolic acid-wrapped CdTe/CdS quantum dots (Q-dots). In the absence of DA, the thioglycolic acid-wrapped CdTe/CdS Q-dots exhibit the high fluorescence spectrum and low RRS spectrum, so are selected to develop an easy-to-get system. In the presence of DA, the thioglycolic acid-wrapped CdTe/CdS Q-dots and DA form a complex through electrostatic interaction, which result in the RRS intensity getting enhanced significantly with new RRS peaks appearing at 317 and 397nm; the fluorescence is powerfully quenched. Under optimum conditions, the scattering intensities of the two peaks are proportional to the concentration of DA in the range of 0.0061–3.0μgmL−1. The detection limits for the two single peaks are 4.1ngmL−1 and 3.3ngmL−1, while that of the DWO-RRS method is 1.8ngmL−1, indicating that the DWO-RRS method has high sensitivity. Besides, the fluorescence also exhibits good linear range from 0.0354 to 10.0μgmL−1 with a detection limit of 10.6ngmL−1. In addition, the system has been applied to the detection of DA in milk samples with satisfactory results.