Magnetic Nanoparticle Based Electrochemical Conversion Method For Detection Of Antibiotic Residues In Poultry Products

With the increase of animal-derived food consumption,antibiotics are generally used in farm animals for therapeutic and prophylactic purposes.Although antibiotics are effective in treating animal disease,potential residues could exist in animal-derived food in case of abuse and misuse,which may cause adverse effects and an increase on bacterial resistance.In this thesis,enrofloxacin(ENR)was used as an antibiotic residue model to investigate the performance of sulfosalicylic acid in the pretreatment of chicken tissues.An electrochemical conversion method based on magnetic nanoparticles(MNPs)was developed with screen-printed electrode.Finally,an electrochemical biosensor was proposed based on the electrochemical conversion method for detection of ENR residues in chicken tissues.1.A simple,rapid sample pretreatment method for the detection of ENR was developed.Sulfosalicylic acid was used to reduce the protein matrix from chicken tissues.In order for portable and in-field detection,and membrane filtration was used to purify the extract.Compared with the pretreatment procedure in the national standard,this method was time-saving and cost-effective.The whole sample pretreatment procedure could be finished in less than 15 min.This method showed high potential for in-field detection.2.A universal method of electrochemical conversion for MNPs accompanying with a newly designed 3D-printed electrochemical cell was proposed.By electrochemical generation of acid,Fe₃O₄ MNPs can react with H⁺and produce ferric/ferrous ions,which further react with K₄Fe(CN)₆ to yield Prussian blue(PB)through potential cycling.The electrochemical conversion method worked well on both home-made and commercial MNPs with different sizes.Interestingly,an uneven deposition of PB on the working electrode and undesired contamination of the reference and counter electrodes were found when using commercial integrated three-electrode chip.The 3D-printed electrochemical cell was proven to solve the problem above through spatial separation of the electrodes.An electrochemical sensor for H₂O₂detection based on the catalysis ability of PB exhibited a linear response from 5?M to1000?M,and a lower detection limit of 0.16?M,which suggests its promising application in electrochemical analysis.3.Combined with the result of the previous chapter,an electrochemical biosensor was developed based on electrochemical conversion of MNPs for detection of ENR residues in chicken tissues.In the sample preparation step,sulfosalicylic acid was used to reduce the matrix effect,and the ENR was concentrated by MNPs.In the detection step,the MNPs could generate signal through electrochemical conversion treatment.Under optimized conditions,the biosensing method allowed for sensitive detection of ENR in a linear range from 0.1 ng/m L to 1000 ng/m L with a limit of detection of 0.02ng/m L.The proposed biosensing method provides a rapid and sensitive approach for detection of antibiotic and has the potential of application in poultry supply chain.