Hydrothermal treatment of red lentils for the synthesis of fluorescent carbon quantum dots and its application for sensing Fe3+

Abstract

In this paper we have reported a simple, one step, non toxic, cheaper and greener route method to synthesize water soluble nitrogen doped carbon quantum dots (N-CQDs) using red lentils as a precursor through hydrothermal method for the first time. The prepared N-CQDs under UV lamp of the wavelength 365 nm shows bright blue fluorescent and quantum yield calculated comes out to be 13.2%. The as prepared N-CQDs shows excitation dependent emission properties and were characterized by Transmission Electron Microscopy (TEM), X-ray Photon spectroscopy (XPS), Fourier Transform Infrared spectroscopy (FT-IR), UV–Vis absorption spectroscopy and Spectroflurophotometry. These N-CQDs gives high response to Fe3+ ions and lead to fluorescence quenching. This quenching mechanism was used to develop a nano probe sensor for successful sensitive and selective detection of Fe3+ ions. The limit of detection (LOD) calculated is 0.10 μM in the dynamic range 2–20 μM with correlation coefficient R2 (0.993). The stability of the present sensor was tested under the effect of ionic concentration and pH which shows that it is stable in high salt conditions and there is no effect of pH to our sensor. This sensor can play an important role in regulating concentrations of iron in order to monitor health of the human body.