Green synthesis of fluorescent carbon dots using chloroplast dispersions as precursors and application for Fe³⁺ ion sensing

Abstract

Water‐soluble carbon dots (CDs) were synthesized using a one‐step hydrothermal treatment of chloroplast dispersions extracted from fresh leaves as a green carbon source. The CD solution showed an emission peak centred at 445 nm when excited at 300 nm. The synthesized CDs were uniform and monodispersed with an average size of 5.6 nm. When adding ferric(III) ions (Fe3+) to the solution of the original CDs, the fluorescence intensity decreased significantly. Based on the linear relationship between fluorescence intensity and concentration of Fe3+ ions, an effective method for rapid, sensitive and selective Fe3+ sensing in aqueous solution could be established. Under optimum conditions, the extent of the fluorescence quenching of prepared CDs strongly depended on the Fe3+ ions over a wide concentration range 1.0–100.0 μM with a detection limit (3σ/k) of 0.3 μM. Furthermore, the quantitative determination of Fe3+ ions in environmental water samples was realized.

The synthesis and modification of highly fluorescent carbon quantum dots for reversible detection of water‐soluble phosphonate‐1‐hydroxyethane‐1,1‐diphosphonic acid by fluorescence spectroscopy

“…To get insight into the quenching mechanism of Fe 3+ on CQDs preliminarily, the Stern–Volmer model (F 0 /F 1 versus [Fe 3+ ]) was displayed as Equation (2): where K SV is the Stern–Volmer constant and [Q] is the the quenching agent concentration [46] . Taking into account the similar expressions of dynamic quenching and static quenching in the Stern–Volmer plot, the specific value of K SV needs to be calculated to determine the mechanism of the quenching process.…”

Tunable multicolour S/N co‐doped carbon quantum dots synthesized from waste foam and application to detection of Cr3+ ions

“…CQDs have the potential to replace traditional semiconductor quantum dots due to their excellent properties such as low toxicity, good biocompatibility, a bright and stable fluorescence, and controllable emission spectrum. [5][6][7][8] These properties allow CQDs extensive application in photocatalysis [9] , cell imaging [10,11] , optical sensor [12] , catalysis [13] , fluorescent inks [14] , ion detection [15] , and small molecule detection. [16,17] Various synthesis methods have been reported for preparing fluorescent CQDs, including acidic oxidation [18] , electrochemical synthesis [19] , and microwave, ultrasonic [20,21] , and hydrothermal methods [22] , laser ablation [23] , hot injection, and pyrolysis.…”

Highly sensitive and selective fluorescence sensing and imaging of Fe3+ based on a novel nitrogen‐doped graphene quantum dots

“…. [13][14][15][16] For example, Liao and colleagues prepared GQDs through pyrolysis treatment using citric acid as a carbon source to sense Fe 3+ . [17] Zhang and colleagues synthesized nitrogen/phosphorus-doped carbon dots (N, P-CDs) by carbonizing maize starch and achieved the sensitive detection of Fe 3+ in water.…”