Design Of BiVO₄ Based Photoelectrochemical Sensor And Detection Of Chlortetracycline

Chlortetracycline residues in food and environment poses a great threat to human health and ecological environment security.The traditional chromatographic detection method is complicated in operation,expensive,and slow in detection speed,which cannot meet the needs of on-site and fast detection.Electrochemical sensor technology has become a research hotspot in the field of antibiotic residue detection because of its advantages of low detection cost,fast detection speed,portable equipment,simple operation and high sensitivity.In this paper,the BiVO₄ based photoelectrochemical sensor with strong portability,fast detection speed,high sensitivity,simple operation and low cost was designed and constructed,and it was successfully applied to the detection of chlortetracycline residue in actual samples.The main research contents of this paper are as follows:?1?Porous BiVO₄ microtubes materials modified with multiple inorganic acids were successfully prepared by electrostatic spinning and simple water bath heating,which have a large specific surface area and can provide more reactive sites for subsequent detection.The principle of multiple acid modification to improve the photoelectric response of materials was revealed through various characterization techniques:The ionization of the hydroxyl group of the inorganic acid in water will cause a large amount of negative charge on the surface of BiVO₄,thereby forming a negative electrostatic field.Under the action of this electric field,positively charged holes accelerate to the surface of the material,which effectively avoids the recombination of holes and electrons,and the efficiency of photo-generated electron-hole separation is significantly improved.Further,the charge transport performance is improved and the photoelectric response of the material is greatly enhanced.?2?The BP-BVO photoelectrochemical sensor was constructed using BiVO₄modified with multiple inorganic acids.Through a variety of characterization methods,the detection mechanism of chlortetracycline was revealed:The modification of inorganic acid improves the separation efficiency of carriers and promotes the reaction of holes with water to form hydroxyl radicals.Under the combined action of holes and hydroxyl radicals,the oxidation of chlortetracycline in the detection system can be achieved.Since holes are consumed in large amounts to avoid recombination with electrons,electrons can be transmitted to the electrode to form the photocurrent.Effective detection of chlortetracycline can be achieved by constructing the corresponding relationship between response photocurrent and chlortetracycline concentration.By optimizing the electrolyte,pH condition,test voltage and enrichment time in the detection of chlortetracycline,the optimal test conditions were obtained,and the different concentrations of chlortetracycline solution were determined under the conditions.In the concentration range of 0.1²10?M,the linear relationship between chlortetracycline concentration and response photocurrent is?I=0.004095C+0.05550,the correlation coefficient is 0.9989,the sensitivity is 4.095?A/?M,and the detection limit of the sensor is as low as 0.06?M?S/N=3?.The results of selectivity,reproducibility and stability are also satisfactory.In the detection of milk and chicken,the sensor shows excellent detection performance,reflecting its great practical application potential.This study provides a feasible reference for the design and construction of electrochemical sensors for detecting other antibiotic residues.