Development of Bile-Salts Templated Green Fluorescent Copper Nanoclusters for Selective Detection of 4-Nitrophenol in Nanomolar Range

Abstract

Green-emissive Copper Nanoclusters (CuNCs) which are eco-friendly, green and simple to produce have been synthesized at room temperature from two naturally occurring bile salts, sodium cholate (NaC) and sodium taurocholate (NaTC) acting as encapsulating ligands. The particle size of both CuNCs was examined by a high-resolution transmission electron microscope (HRTEM) analysis. The surface functional groups and composition of both the as-prepared CuNCs were determined by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopic techniques. Both of the prepared CuNCs showed good pH stability and ionic strength. Both nanoprobes have high sensitivity and selectivity for the determination of 4-Nitrophenol (4-NP) which is a major environment pollutant. The values of quantum yield and average lifetime have been evaluated to confirm that the quenching mechanism is inner filter effect (IFE). Based on this, simple and accurate turn-off fluorescent nanoprobes, NaC encapsulated CuNCs and NaTC encapsulated CuNCs were created to detect 4-NP with a detection limit of 47.1 nM and 58.4 nM, respectively. Therefore, the developed nanoprobe may be applied for on-site and fast detection of 4-NP.