Electrochemical Biosensors For Detection Of Veterinary Drug And Pesticide Residues Based On Screen-printed Carbon Electrodes

It is very important to develop sensitive, highly selective, convenient, good precision and effective determination methods for measurement of ultra-content veterinary drug residues (such as, chloramphenicol, CAP) and pesticide residues (such as, organophosphorus pesticides, OPs) in food, Which is benefitable for health protection, green barrier broken and export promotion.Electrochemical biosensors fabricated on screen printed cabon electrodes (SPCEs) has the advantages of integration of electrodes, simple manipulations, low cost and low consume of sample, which can be used for one step determination then discarded. It is very suitable for fabricating various veterinary drug and pesticide residues biosensors.In this paper, we fabricated several disposable electrochemical biosensors based on SPCEs for determination of CAP in milk samples and Ops in cabbage samples. The detailed materials are shown as follows: In chapter 1, the recent advances in both detection of veterinary drug and pesticide residues were reviewed.In chapter 2, a disposable amperometric immunosensor was fabricated by Nafion membrance and gold nanoparticles (AuNPs) coated chloramphenicol-bovine serum albumin(CAP-BSA) modified SPCEs(SPCEs│Nafion/AuNPs/CAP-BSA), which was employed to determine CAP in real milk samples and the recovery rates exhibited a range of 88%~102%. The results were consistent to the high performance liquid chromatography(HPLC) method.In chapter 3, a magnetic field controlled and disposable amperometric immunosensor was fabricated by carbon nanotubes (CNTs)/ferrocene(Fc)/Nafion -Membrane coated on SPCEs, and then Fe3O4/Au (GMP) composite nanoparticle coated CAP-BSA was absorbed on it through external magnetic field for the determination of CAP (SPCEs│CNTs/Fc/Nafion│GMP-CAP-BSA). The immunosensor was employed to determine CAP in milk samples and the recovery rates exhibited a range of 88%~104%. The results were consistent to the HPLC method.In chapter 4, the composite magnetic particulate composed of Fe3O4/Au/acetylcholinesterase (AChE) was synthesized and was absorbed on SPCEs coated CNTs/ZrO2/prussian blue (PB)/Nafion-membrane through magnet. A disposable OPs enzyme biosensor has been developed for the determination of dimethoate based on it (SPCEs│CNTs/ZrO2/PB/Nafion│GMP-AChE). The enzyme biosensor was used to determine OPs in cabbage samples and the results were accord with the gas chromatography(GC) method. The convenient, fast and sensitive voltammetric measurement opens a new method for OPs analysis.