Green synthesis of photoluminescent carbon dots derived from red beetroot as a selective probe for Pd2+ detection

Abstract

Recently, the development of green methods for carbon dots (CDs) synthesis using natural precursors has received considerable attention. In this regard, fluorescent CDs with high quantum yield have been synthesized from Red Beetroot as a natural precursor via a low-cost, simple, and green one-step hydrothermal treatment. The prepared CDs with a size range of 5–7 nm exhibited significant advantages, including great water solubility, low cytotoxicity, high quantum yield (27.6%), incredible resistance to pH alteration, high salty environments, and photobleaching. The fluorescence emission wavelength with maximum intensity for CDs was 525 nm at the excitation wavelength of 450 nm. These green-emitting CDs were employed for selective and sensitive measurement of Pd2+ in an aqueous solution. The addition of Pd2+ resulted in fluorescence quenching of CDs through a static quenching mechanism with an acceptable limit of detection of 33 nM in a linear range from 3 μM to 43 μM. Also, the proposed fluorescent probe can be applied as a suitable sensor for measuring Pd2+ ions in Mineral and Well water samples with satisfactory recovery rates from 96.6 to 105.0%. Generated fluorescent CDs have been used as an attractive biocompatible label for cellular imaging and showed an excellent quenching response by the addition of Pd2+ ions. As a result, the proposed CDs-based probe could be utilized in various environmental applications.