In this work, the tube-filled nanocomposites Co 3 O 4 @CNTs were successfully prepared and applied for the first time in the permonosulfate (PMS) system to degrade norfloxacin (NX). Characterization results showed that Co 3 O 4 nanoparticles served as independent templates and were randomly distributed onto the surface of the internal cavity of CNTs. After five cycles, the removal rate of NX decreased by only 4.5%, indicating its high catalytic activity and stability. This study also proposed a potential mechanism based on Co 3 O 4 @CNT/PMS system catalysis in which 1 O 2 was the main cause of NX degradation. DFT calculation results confirmed that the electronic activity of Co 3 O 4 filled CNTs increased, and that the Co 3 O 4 nanoparticles filled in the tube were the main catalytic sites of Co 3 O 4 @CNTs for NX degradation. This work provided the first insight into the effects of metal nanoparticles in the confined structure of CNTs on PMS activation.
Yifei Ma,Lijie Zhang,Hong Yang,Shanshan Zhu,Jinhua Liu
Highly selective and sensitive determination of dopamine (DA) from multiple sources remains a persistent and significant challenge. Here, we develop an imidazole-triggered in situ fluorescence reaction system for highly selective and sensitive determination of DA from various sources (human, horse, dog, rabbit, and mouse). The system operates by catalyzing the oxidation of DA with 1,5-Dihydroxynaphthalene (1,5-DHA) through a Lewis base formed by imidazole, leading to the rapid generation of yellow azamonardine fluorescent compounds (AFC). Notably, the system demonstrates minimal background noise and a high signal-to-noise ratio of up to 300-fold with a determination limit of 33.33 pM, making it 10-100 times more sensitive than conventional enzyme-linked immunosorbent assay (ELISA) methods. Moreover, selectivity tests reveal that our system can effectively distinguish between several common interfering substances, even at concentrations as low as 10 nM. The developed system shows promising results in detecting DA from diverse sources (humans, horses, dogs, rabbits, and mice), including urine samples from clinical patients, exhibiting good agreement with traditional ELISA kits. Therefore, the established in situ fluorescence reaction system holds great potential for the determination of DA-related disorders due to its impressive analytical capabilities.
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