Double-signal quantification of amoxicillin based on interaction with 4-aminoantipyrine at copper and nitrogen co-doped carbon quantum dots as an artificial nanozyme

• Published in: Mikrochimica acta (1966) Vol. 189; no. 5; p. 183
• Main Authors: Mahmoud, Ashraf M., El-Wekil, Mohamed M., Ali, Ramadan, Batakoushy, Hany A., Shahin, Reem Y.
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.05.2022; Springer; Springer Nature B.V
• Subjects: Amoxicillin; Ampyrone; Analytical Chemistry; Antibiotics; Carbon; Catalytic activity; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Colorimetry; Copper; Emission; Fluorescence; Humans; Hydrogen Peroxide; Microengineering; Nanochemistry; Nanotechnology; Nitrogen; Original Paper; Oxidizing agents; Penicillin; Peroxidase; Quantum Dots; Water sampling; Peroxidase-like activity; Hydrothermal; Dual-read assay; Copper and nitrogen co-doped carbon quantum dots; Amoxicillin
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-022-05253-1

An one-pot hydrothermal method was developed for synthesis of carbon quantum dots co-doped with copper and nitrogen (Cu, N@CQDs). The synthesized Cu, N@CQDs has unique advantages such as high fluorescence quantum yield (39.1%) and high catalytic activity. Oxidative coupling of amoxicillin (AMX) with 4-aminoantipyrine (4-NH 2 -APE) in the presence of H 2 O 2 as an oxidant to produce pink quinoneimine chromogen was carried out with the aid of Cu, N@CQDs as a peroxidase-like catalyst. This system was used for the colorimetric and fluorometric assays of AMX with reliable results. Colorimetric method is based on the measurement of a pink-colored product at λ max  = 505 nm while the fluorometric assay is based on the quenching of the fluorescence emission of Cu, N@CQDs at 440 nm after excitation at 370 nm. For the colorimetric method, the absorption intensity linearly increased over the concentration range 4.3–110.0 µM with LOD (S/N = 3) of 1.3 µM. For the fluorometric method, the emission intensity of Cu, N@CQDs linearly decreased upon addition of AMX in the concentration range 0.2–120.0 µM with a limit of detection (LOD, S/N = 3) of 0.06 µM. The proposed system was applied to the determination of AMX in different real samples such as pharmaceutical capsules, human serum, milk, and conduit water samples with recoveries in the range 95.8–104.1% and relative standard deviation (RSD %) less than 4.1%. Graphical abstract