Chinese Journal of Applied Chemistry ›› 2022, Vol. 39 ›› Issue (8): 1285-1293.DOI: 10.19894/j.issn.1000-0518.210353

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Synthesis of Ruthenium‑Graphene Quantum Dots Artificial Oxidase and Its Application in Colorimetric Detection of Phoxim in Carrots

Wen-Dong WANG, Zai-Jun LI()   

  1. School of Chemistry and Materials Engineering,Jiangnan University,Wuxi 214125,China
  • Received:2021-07-21 Accepted:2021-12-07 Published:2022-08-01 Online:2022-08-04
  • Contact: Zai-Jun LI
  • About
  • Supported by:
    the National Key Research and Development Program of China(2018YFC1603001)


The histidine functionalized graphene quantum dots (His-GQDs) react with ruthenium trichloride to form a stable ruthenium complex. This complex is treated in a N2 atmosphere at 600 ℃ for 1 h to obtain a ruthenium-graphene quantum dot composite (Ru-His-GQD). The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis demonstrate that Ru-His-GOD has one three-dimensional structure. The diameter of ruthenium nanoparticles is between 40 and 60 nm. Ru-His-GQD is rich in functional groups and has high oxidase-like activity. Based on Ru-His-GQD catalyzed oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to produce blue compounds, a photometric method for the determination of phoxim in carrots is established. Phoxim can inhibit the activity of Ru-His-GQD oxidase, resulting in a decrease in the absorbance of the blue compound. When the concentration of phoxim is between 30~240 μg/L, the absorbance of the oxidation product of TMB at 652 nm decreases linearly with the increase of phoxim concentration. The detection limit of the method reaches 7.33 μg/L (S/N=3), and the sensitivity is higher than those in literature. It has been successfully applied to the detection of phoxim in carrots.

Key words: Pesticide detection, Functionalized graphene quantum dots, Ruthenium nanoparticles, Phoxim, Colorimetric sensor

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