Portable sensor for the detection of picric acid using fluorescent carbon dot embedded PVA film

The current work emphasizes the development of a carbon dot incorporated portable polymer film for the sensitive and selective detection of picric acid (PA) in aqueous solutions. Nitrogen doped fluorescent carbon dots (WCD) were synthesized from white curcumin via hydrothermal method and characterized using HRTEM, FTIR, XRD, Raman and XPS. This promising scaffold can detect picric acid (PA) via fluorescence quenching, in nanomolar range, with a limit of detection (LOD) of 4.55 ppb (19.9 nM), demonstrating sensitivity far below the permissible limit of 0.5 ppm in drinking water. The quenching mechanism is rationalized by a cumulative effect of the inner filter effect and other secondary interactions. Successful incorporation of WCD into the polymer polyvinyl alcohol (PVA) matrix resulted in a fluorescent WCD/PVA film, and acts as a promising candidate for portable, real-time environmental sensing applications. The fluorescence studies on the WCD/PVA film affirm its practicability for on-site sensing by exhibiting fluorescence quenching in 25 nM PA solution which is near to the LOD of WCD solution.