Guangli Li,Nayu Chen,Yafeng Zhang,Tianyu Wang,Rui Zhu,Yuan Jin,Nanke Ma
Rhodamine B (RhB) is highly carcinogenic and is therefore prohibited as a food colorant. Hence, it is necessary to establish a simple but effective technique for the sensitive determination of RhB in foodstuff. Herein, an efficient voltammetric platform was established for the detection of RhB in chili oil based on flower-like β-Bi 2 O 3 microsphere/multiwalled carbon nanotube composites (β-Bi 2 O 3 /MWCNTs). Various microscopic and spectroscopic techniques confirmed the successful formation of β-Bi 2 O 3 /MWCNTs. Owing to the synergistic effect from β-Bi 2 O 3 microspheres and MWCNTs, the β-Bi 2 O 3 /MWCNTs demonstrated superior electrocatalytic activity for the oxidation of RhB as compared to the individual components. Electrochemical kinetics tests confirmed that the RhB electrooxidation was governed by an irreversible and adsorption-controlled process, and involved two electrons one proton transfer pathway. The oxidation peak currents of RhB were linearly correlated with RhB concentrations ranging from 0.05 to 100 μM with a low limit of detection (0.002 μM). The β-Bi 2 O 3 /MWCNT demonstrated strong anti-interfering ability against other azo colorants, and retained robust voltammetric responses for at least 14 days. Moreover, the concentrations of RhB in chili oil were accurately detected by the β-Bi 2 O 3 /MWCNT via second-order derivative linear scan voltammetry with satisfactory recovery. Overall, the β-Bi 2 O 3 /MWCNT/GCE shows great potential for in-situ analysis of trace amounts of RhB in various food matrices.
Yang Fan,Zhang Jun-Ning,Zhang Chao,Xu Xin-Da,Li Bing,Yang Woochul,Xie Wan-Feng
Real-time detection of acetic acid vapor is of concern for ensuring environmental and personal safety. However, acetic acid gas sensors, particularly those based on Bi 2 O 3 , often fail to meet practical performance requirements owing to their slow response characteristics and high operating temperature. To enhance sensing performance, highly permeable Bi 2 O 3 microspheres decorated by Pt-nanoparticles are rationally synthesized by a facile template method. Among the fabricated sensors, the one based on 3 wt% Pt-decorated Bi 2 O 3 demonstrated excellent sensing performance. Specifically, the sensor displayed high selectivity for acetic acid, rapid response and recovery times (22.5 and 9 s, respectively), strong resistance to interference, and good long-term stability at a low operating temperature (150 °C). Notably, the sensor exhibited an exceptionally high response of 126 to 100 ppm acetic acid—the highest reported value for Bi 2 O 3 -based sensors tested at a relatively low operating temperature in recent years. These results demonstrate that Pt-decorated Bi 2 O 3 holds strong potential for use in high-performance acetic acid sensors. Graphical abstract
危险品化学品经营许可证（带存储）