A rapid colorimetric method for the detection of deltamethrin based on gold nanoparticles modified with 2-mercapto-6-nitrobenzothiazole
In this study, we developed a rapid colorimetric method for the detection of deltamethrin using gold nanoparticles modified with 2-mercapto-6-nitrobenzothiazole (Au NPs–MNBT): deltamethrin adhered onto the surface of Au NPs–MNBT and a core–shell structure formed with Au NPs–MNBT as the core and deltamethrin as the shell. The formation of the core–shell structure caused the change of solution color and UV-visible absorption spectra of Au NPs, which can be used to quantitatively detect deltamethrin by the naked eye and using a UV-Vis spectrophotometer. The effect of MNBT content, detection pH and reaction time on the detection of deltamethrin was studied in detail, and the selectivity and anti-interference ability of the probe were tested. The results showed that the probe can be used to detect deltamethrin rapidly and accurately from 13 kinds of other pesticides. The detection of deltamethrin was not affected when 5 times the concentration of other pesticides coexisted with deltamethrin. The detection limit of deltamethrin was observed to be 0.25 μM by the naked eye and 0.005 μM by UV-Vis spectroscopy. The extract solutions of small tomato and cherry were used to evaluate the feasibility of this detection method in actual samples and the results were consistent with that of gas chromatography-mass spectrometry, which proved that the developed method has actual sample application potential for deltamethrin detection.