A novel electrochemical sensor for selective determination of uranyl ion based on imprinted polymer sol-gel modified carbon paste electrode

In this work, an electrochemical sensor by combining sol-gel processing and paste electrode was developed. Functional precursor was first synthesized and reacted with tetramethoxysilane to obtain polymer sol-gel and then used as a receptor for selective binding and sensing of uranyl ion in aqueous solution. Ion-imprinted polymer sol-gel synthesized in the presence of uranyl ion was characterized by Fourier transform-infrared spectroscopy, scanning electron microscopy and N₂ adsorption-desorption analysis by comparing with non-imprinted sol-gel obtained in the absence of uranyl ion. Surface area, pore volume and diameter were analyzed from the profile of nitrogen adsorption. Uranyl ion imprinted network was employed to achieve a suitable conformation for electrochemical reduction of uranyl ion and also to improve the selectivity of the sensor. The results showed that the ion imprinted polymer sol-gel modified carbon paste electrode exhibited selectivity toward uranyl ion compared to electrode containing non-imprinted polymer sol-gel. The ion-imprinted sensor was also successfully employed to detect uranyl ion in real samples and exhibited distinctive change in current upon interaction with uranyl ion. The corresponding selectivity factors of the sensor toward uranyl ion against the other analogues were evaluated.