Development of Highly Efficient Dual Sensor Based on Carbon Dots for Direct Estimation of Iron and Fluoride Ions in Drinking Water. Issue 15 (17th April 2019) - Sarkar, Probir Kumar
Abstract: The fluorescent nanomaterial carbon dots (CDs) have attracted tremendous attention in the recent times because of their unique physico‐chemical characteristics. Highly fluorescent CDs were prepared through a simple and nontoxic one‐step hydrothermal carbonization of polyvinylpyrrolidone (PVP). The as‐synthesised CDs, without any pre‐treatments or post‐treatments, show high stability over a broad pH range and have an excellent potential in chemical sensing applications. The as‐prepared CDs have been demonstrated to be an excellent nano probe for Fe 3+ ions sensing in aqueous media based on the fluorescence quenching with high sensitivity (lower limit of detection ∼ 1 μM) and selectivity towards Fe 3+ ions. "Turn off" fluorescence arises due to the formation of CDs‐Fe 3+ nanocomposite complex in the solution. The nanocomposite complex forms by the attachment of Fe 3+ ions to the surface emissive site of the CDs, resulting in an obvious fluorescence quenching. Here, CDs itself act as a promising nano carrier for loading of Fe 3+ ions to form the CDs‐Fe 3+ nanocomposite complex in the solution. In addition to all, in this study we are intensely focused to explore the application of CDs‐Fe 3+ nanocomposite complex. We have used the CDs‐Fe 3+ nanocomposite complex as a novel sensor probe for the detection of F ‐ ions in aqueous media based on "Turn on" fluorescence mechanism. "Turn on" fluorescence occurs due to the formation of thermodynamically highly stable [FeF6 ] 3‐ complex and bare CDs in the solution. The developed sensor has high sensitivity (lower limit of detection ∼ 1 μM) and selectivity towards F ‐ ions over a wide‐ranging other competing anions. Finally, we successfully demonstrate the real life application of the developed sensor by estimating the trace F ‐ ions in the real world drinking water samples. Abstract : Highly fluorescent carbon dots with a high quantum yield, excellent water solubility and good photostability were prepared through one step hydrothermal carbonization of PVP. We have successfully developed a simple, cost‐effective, extremely selective and sensitive "Turn off" and "Turn on" dual fluorescence sensor for direct detection of Fe 3+ and F ‐ ions in aqueous medium. The developed sensor has also great potential applications in estimating trace F ‐ ions in real world drinking water samples.