Development of a fluorescence-linked immunoassay based on quantum dots for fenvalerate

The glutathione-coated CdTe quantum dots (QDs) were synthesized in a paper. After purification, the QDs were coupled with monoclonal antibody to fight against fenvalerate. The conjugates had the same emission wavelength as that of QDs. The excitation wavelength and emission wavelength of the conjugates were determined to obtain the highest signal-to-noise ratio. After the antibody concentration optimization, the fluorescence-linked immunoassay method was developed. The method used the QDs as the signal to quantify the fenvalerate. Compared with the enzyme-linked immunosorbent assay (ELISA), it saved more than 1 h and decreased the false-positive rate using the specified emission wavelength of QDs. The 50% inhibitory concentration (IC₅₀) of the method was 0.28 µg mL⁻¹. The detection limit was 25 ng mL⁻¹ and the linear range was 60 ng mL⁻¹–3.83 µg mL⁻¹. Via preliminary application, fenvalerate residues in spiked samples were determined. The recovery of fenvalerate in water samples ranged from 84.5% to 96.2% and that in vegetables ranged from 72.5% to 125.7%. It was a rapid detection of the fenvalerate residue in environment and vegetables.