| With the development of economy and the increase of people's living standard,the food safety issue has become the focus of social concerns,from which the safety of animal-derived foods has received widespread attention.The safety of animal-derived foods is mainly caused by residues of veterinary drugs,which are originated from the abuse of veterinary drugs because of economic benefits.The residual veterinary drugs have caused serious influence to human and the environment.Therefore,it is very important to establish the strategy to detect veterinary drug residues rapidly and sensitively.In this paper,combined with flow injection method,the detection strategy for veterinary drug residues was established based on the inhibiting or sensitizing effects of four veterinary drug residues on different chemiluminescence systems of Luminol.The main contents and experimental results are listed as follows:1.Based on the fact that praziquantel can effectively inhibit the chemiluminescenceintensityofLuminol-NaIO4,anovelflow injection-chemiluminescence method for the determination of praziquantel was established.Under the optimal experimental conditions,there was a good linear relationship between the relative intensity of chemiluminescence and the concentration of praziquantel in the range of 4.0×10-81.0×10-66 mol/L,with the limit of detection?LOD?was 9.9×10-9 mol/L.The relative standard deviation?RSD?was 1.44%for the determination of 2.0×10-7 mol/L praziquantel?n=11?.This method is simple,rapid and cheap,which has been successfully applied to the detection of praziquantel in pig feed samples with the recoveries was ranged from 98.5%to 100%.In addition,the mechanism of the system was investigated by UV and chemiluminescence spectra.Luminol reacted with NaIO4 in alkaline environment firstly to form an excited 3-aminophthalic acid ion?3-APA*?and emit light at 425 nm.Then the addition of praziquantel could reduce the production of 3-APA*and thus inhibit the luminescence of Luminol-NaIO4system.2.A new flow injection-chemiluminescence method for the determination of sulfabenzamide was developed based on the inhibition of sulfabenzamide on typical Luminol-H2O2 chemiluminescence system.Under the optimum experimental conditions,there was a good linear relationship between the relative intensity of chemiluminescence and the concentration of sulfabenzamide in the range of 3.0×10-88.0×10-7 mol/L,with the limit of detection was 1.24×10-9mol/L.The relative standard deviation was 0.72%for the determination of 5.0×10-7 mol/L sulfabenzamide?n=11?.At the same time,the interferences of various ions and amino acids on the determination were also investigated,within the allowable range of errors,no effect was observed.Moreover,the chicken serum sample was determined by the proposed method and the recoveries ranged from99.9%to 101.3%.In addition,the mechanism of the luminescent system was studied too,it was found that the luminophor of the system was 3-APA*,an oxidation product of Luminol.3.Based on the fact that ceftiofur sodium can effectively inhibit the luminous intensity of Luminol-hydroxylamine hydrochloride,a method for the determination of ceftiofur sodium was established.After optimizing the experimental conditions,there was a good linear relationship between the relative intensity of chemiluminescence and the concentration of ceftiofur sodium in the range of 1.0×10-71.0×10-55 mol/L,with the limit of detection was 8.45×10-8mol/L.The relative standard deviation was 1.00%for the determination of2.0×10-66 mol/L ceftiofur sodium?n=11?.The cattle serum sample was determined by the proposed method and the recoveries ranged from 98%to 102.5%.In addition,after studying the mechanism of luminescence,it was found that there was a competitive relationship between ceftiofur sodium and Luminol,as ceftiofur sodium would compete with Luminol and react with O2?-,produced by hydroxylamine hydrochloride and O2 in solution,thus inhibiting the luminescence of the system.4.Based on the fact that thiamphenicol could enhance the luminescence intensity of Luminol-H2O2,a novel method for the determination of thiamphenicol was developed.Under the optimal experimental conditions,there was a good linear relationship between the relative intensity of chemiluminescence and the concentration of thiamphenicol in the range of1.0×10-101.0×10-88 mol/L,with the limit of detection was 8.1×10-11 mol/L.The relative standard deviation was 0.34%for the determination of 1.0×10-9 mol/L TAP?n=11?.The milk sample was determined by the proposed method and the recoveries ranged from 99.3%to 104%.Furthermore,the method of detecting thiamphenicol by UV-Vis spectrophotometer was also compared.The research showd that the results are similar,indicating that the method has high accuracy.In summary,a flow injection-chemiluminescence analysis technology was established to detect several veterinary drug residues in this paper.This method not only has the advantages in operating simply and conveniently,but also fast and sensitive,which possess a potential application in the detection of other veterinary drug residues.In addition,the luminescence mechanism of each system was also investigated by UV spectroscopy and chemiluminescence spectroscopy.It was found that all the luminophor of several different Luminol luminescence systems is 3-APA*,an oxidation product of Luminol. |
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