Piperidine–calix [4] arene modified gold nanoparticles: Imidacloprid colorimetric sensing

A novel piperidine-calix [4] arene was synthesized by the Mannich reaction. Then, piperidine-calix [4] arene modified gold nanoparticles (PPC-Au NPs) were designed and synthesized through click reaction. The resulting gold nanoparticles were characterized by UV–vis spectroscopy, IR spectroscopy, transmission electron microscopy (TEM). The newly synthesized gold nanoparticles had a cooperative effect on recognition of imidacloprid resulting in appreciable changes in color. The advantage of our experiments over classical assays is it can realize the prompt on-site and real-time detection of imidacloprid with high sensitivity (5.0 × 10−6 M) and selectively. The developed method was also successfully applied for detecting imidacloprid in tape water with a detection limit of 2.5 × 10−5 M.

Graphical abstractA simple and visible strategy of a highly selective and sensitive for imidaclorid colorimetric probe based on piperidine-calix [4] arene modified gold nanoparticles (PPC-Au NPs) was developed. We synthesized piperidine-calix [4] arene modified gold nanoparticles through click reaction. The use of upper rims of the piperidine-calix [4] arene cavity, imidacloprid molecule would be wrapped up the surface of PPC-Au NPs causing Au NPs to reunion. The detection system presents excellent selective ability (5.0 μM) when with a series of interfering pesticides. The developed method was also successfully applied for detecting imidacloprid in tape water with a detection limit of 2.5 × 10−5 M. Thus, we successfully achieved the colorimetric detection for imidacloprid on site and real-time.Figure optionsDownload full-size imageDownload as PowerPoint slide