Synthesis of Fluorescent Nanosensor from Deep Eutectic Solvent Assisted Biomass Derived Carbon Dots: Selective and Sensitive Detection of Dual Antioxidants

Abstract

Here, in this study blue fluorescence carbon dots (CDs) were synthesized from clove (Syzygium aromaticum) as a carbon source through facile and green hydrothermal approach by using Deep eutectic solvent (Choline chloride and Urea) in 1:1 molar ratio. No additional harmful and toxic chemicals were used during the synthesis process. The synthesized CDs were characterized through various analytical techniques, such as HR-TEM, FT-IR and XPS. Ultraviolet visible spectrum of CDs showed maximum absorbance at 321 nm due to the conjugation of C=C and C=O of CDs and the shoulder band appears at 400 nm which reveals the blue emission in the range 340 nm to 420 nm. CDs had an average particle size of 2.1 nm with fluorescence quantum yield of ∼22.5 %. Effect of pH, ionic strength, photostability and long term storage studies were also performed and revealed great results. Furthermore, the selectivity and sensitivity studies of the synthesized nanoprobe were done with various metal ions as well as bioactive molecules and it showed high sensitivity and selectivity towards quercetin (QT) and riboflavin (RF) with limit of detection as low as 0.25 μM and 0.14 μM respectively. In this study, facile and green approach was adopted for the synthesis of carbon dots for the selective and sensitive detection of dual analytes (antioxidants) i.e. quercetin (QT) and riboflavin (RF) with very low limit of detection range .