Design of Carbon Quantum Dot Based Fluorescence Sensor for Detection of Toxic Organic Molecules

Abstract

Although extensive work has been done on rapid detection of metal ions, anions and biomolecules using luminescent carbon quantum dots (CD), the available documentation on development of luminescent sensors for the detection of organic pollutants such as pesticides or herbicides is extremely sparse. The main focus of this doctoral research work is to develop new fabrication methods for N-doped carbon dots for sensing some important herbicides and pesticides. We have optimized the fluorescence properties of N-doped carbon dots with respect to precursor concentration. Utilizing the improved emission property of carbon dots we have designed smart nanosensors to detect pesticides in aqueous medium as well as in real agricultural products. We have mainly emphasized on the following issues, 1) low energy and cost effective approach for synthesis of carbon dots, 2) choice of a molecular precursor ensuring the availability of abundant surface functional groups so as to ensure a superior molecular recognition by the target analyte, 3) Incorporating CD in a solid matrix to develop a more stable carbon dot based sensor, 4) to develop suitable fluorescence sensing method for less explored organochlorine pesticides (OC), 5) to develop CD based sensor for detection of pesticides in a microbial cell. In line with our objective we have developed CD based fluorescence nanosensor for detection of two widely used organophosphorus pesticides i.e. glyphosate and quinalphos, one organochlorine pesticide atrazine. The details of sensing conditions, plausible mechanism as well as applications on detection of pesticides in real agricultural samples have been discussed in respective chapters.