Fluorescent Sensing of Pb2+ in Environmental samples by N-doped Carbon Dots: Application of Response Surface Methodology and Doehlert Design

Lead is one of the important heavy metal that use in cosmetics, batteries, ceramics, pipes and smelting. Today, contamination with lead is an important challenge. Both children and adults are at risk of lead poisoning. After breathing in lead-containing dust, lead passes through the lungs into the blood [1]. In this work, a cheap, simple, selective and sensitive turn off fluorescent sensor was presented for Pb2+ determination. N-doped carbon dots (N-CDs) were synthesized by microwave assisted method. Characterization of N-CDs was performed by high resolution transmission electron microscopy and Fourier transform infrared spectroscopy. The important parameter (pH, concentration of carbon dots: CCDs and time) were optimized with Doehlert experimental design and response surface methodology. Optimum condition for maximum turn off was pH 3, CCDs 8 mg mL-1 and 5 min. Limit of detection (LOD) and linear range was 20 nM and 50-25000 nM. Tap, river and mineral water samples were spiked with different concentration of Pb2+ and analyzed by proposed sensor. Suitable recoveries show that the proposed sensor had great capability for analysis of Pb2+ ions in real samples.