Highly crystalline graphitic carbon nitride quantum dots as a fluorescent probe for detection of Fe(III) via an innner filter effect

• Published in: Mikrochimica acta (1966) Vol. 185; no. 2; pp. 134 - 7
• Main Authors: Li, Yuehai, Cai, Jiabai, Liu, Fengjiao, Yu, Huiwu, Lin, Fan, Yang, Hui, Lin, Ye, Li, Shunxing
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.02.2018; Springer; Springer Nature B.V
• Subjects: Analytical Chemistry; Boron nitride; Carbon nitride; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Crystal structure; Crystallinity; Fluorescence; Investigations; Microengineering; Nanochemistry; Nanotechnology; Original Paper; Oxidation; Quantum dots; Size distribution; Water chemistry; Water purification; Liquid exfoliation; Iron; Metal-free semiconductor; Chemical oxidation; Electrostatic interaction; Natural water
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-017-2655-8

Bulk g-C 3 N 4 was transformed into water-soluble graphitic carbon nitride quantum dots (g-CNQDs) via a chemical oxidation and liquid exfoliation process. The g-CNQDs possess a size distribution ranging from 1 to 5 nm (centered at 3 nm), excellent crystallinity, and are water soluble. It is found that Fe(III) ions are adsorbed on the surface of the g-CNQDs via electrostatic interaction, and that the blue fluorescence of the g-CNQDs is reduced by Fe(III) via an inner filter effect. By using the g-CNQDs as a fluorescent probe, Fe(III) can be determined at excitation/emission wavelengths of 241/368 nm in spiked natural water samples within 1 min and with good selectivity over other ions. Response is linear in the 0.2–60 μmol·L −1 Fe(III) concentration range, and the detection limit is 23 nmol·L −1 . Graphical abstract Graphitic carbon nitride quantum dots (g-CNQDs) emit blue fluorescence at an excitation wavelength of 241 nm. Fe(III) ions are quickly adsorbed on the g-CNQDs via electrostatic interaction, and fluorescence is quenched due to an inner filter effect.