Synthesis of Fluorescent Boron, Nitrogen Co-Doped Carbon Nanodots for Detection of Nitrophenols

In this work, we have utilized fluorescent Boron and Nitrogen co-doped Carbon nanodots (BNCDs), for optical detection of nitrophenol isomers (p-NP, m-NP, o-NP) and 2,4,6 trinitrophenol (TNP) in water. We synthesized the BNCDs using one-step hydrothermal treatment of Trimethyl ammine borane (TMAB) at different temperatures (100°C, 150°C, 200°C) for different reaction times (4hrs, 8hrs, 12hrs & 16 hrs). The as-prepared BNCDs dispersion in water were characterized using microscopic and spectroscopic techniques. We observed that these BNCDs synthesized at 200°C displayed a broad fluorescence peak at 400 nm for 350 nm excitation wavelength. In the presence of nitrophenols, we observe strong quenching of the fluorescence of BNCDs with quenching efficiency TNP>p-NP>m-NP>o-NP. We also observed a red shift in fluorescence quenching with minimum shift detected for TNP. From the Sterm-Volmer plot, we determined the lowest level of detection as 21nM and 26nM for TNP and p-NP respectively. To improve the selectivity between TNP and p-NP, pH of BNCDs dispersion was varied.