Sensitive and selective imprinted electrochemical sensor for p-nitrophenol based on ZnO nanoparticles/carbon nanotubes doped chitosan film

Abstract A sensitive and selective molecularly imprinted electrochemical sensor for p-nitrophenol detection has been developed based on ZnO nanoparticles/multiwall carbon nanotubes (MWNTs)-chitosan (CTS) nanocomposite. This nanocomposite was dripped onto an indium tin oxide electrode and then imprinted sol–gel solution was electrodeposited onto the modified electrode to construct the proposed sensor. The morphologies and electrochemical behaviors of the imprinted sensor were characterized by scanning electron microscope, X-ray diffraction, electrochemical impedance spectroscopy, square wave voltammetry and cyclic voltammetry. The imprinted sensor displayed excellent selectivity towards the target molecule p-nitrophenol. Meanwhile, the introduced nanocomposite increased surface area and active sites for electron transfer, thus remarkably enhancing the sensitivity of the imprinted sensor. Under optimal conditions, the peak current was linear to p-nitrophenol concentration ranging from 1.0 × 10 − 8 to 2.0 × 10 − 4  mol·L − 1 with a detection limits of 1.0 × 10 − 9  mol·L − 1 ( S / N  = 3). This proposed sensor was applied to the detection of p-nitrophenol in various water samples successfully.