Green fluorescent sensor based on carbon quantum dots for Cr(VI) determination

In this study, a new, cheap and green fluorescence sensor based on carbon quantum dots was used for Cr (VI) determination. Carbon quantum dots were synthesized from citric acid, polyvidon and boric acid by microwave assisted method. The size of carbon quantum dots estimated by high resolution transmission electron microscope (HRTEM) and was about 10 nm. Fourier transform infrared spectroscopy (FT-IR) was used for study of functional groups on the carbon dot surface. Synthesized carbon dots had excitation and emission peaks at 340 and 440 nm, respectively. Fluorescence quenching process was occurred after adding of Cr (VI) to synthesized carbon dots solution. At optimum condition (pH=3, t=1 min, excitation and emission slit widths = 10 nm, λ excitation =340 nm and λ emission =440 nm), linear dynamic range and detection limit of this sensor were 5-200 µM and 1.24 µM, respectively. Recovery percent was studied in different real samples such as tap water, river water, mineral water and canned fish.