New Analytical Methods For The Determination Of Dimetridazole In Milk Power, Egg And Feed Samples

Dimetridazole (DMZ) is a5-nitroimidazole type veterinary drug, traditionallyused for prevention and treatment of bacterial and protozoal infections in poultry andswine. Because of the capability of improving feed efficiency, DMZ has also beenused as a feed growing pharmaceutical additive. However, studies have shown thatDMZ possesses genotoxic, teratogenic, carcinogenic, and mutagenic effects. And theunreasonable use or abuse of DMZ will result it the drug residue in the food animals,which will pose a threat to human food safety. Currently, many countries, includingChina, United States, and European Union, have banned the use of it in foodproducing animals. Therefore, it is crucial to develop new methods to detecting DMZfor human’s food safety.(1) A novel core–shell magnetic nano-sorbent with surface molecularly imprintedpolymer coating for the selective solid phase extraction and UV-visspectrophotometric determination of dimetridazole. A novel core–shell magneticnano-sorbent with surface molecularly-imprinted polymer coating was prepared via asol–gel process. Methyltrimethoxysilane and3-aminopropyltriethoxysilane were usedas functional monomers, tetraethyl orthosilicate as cross-linker, Al3+as dopant, andthe resulted molecularly-imprinted polymer film was coated on the surface of thenano Fe3O4@SiO2particals in the presence of template molecule (Dimetridazole).Al3+as dopant to generate Lewis acid sites in the silica matrix for the metalcoordinate interactions with the template dimetridazole (DMZ). The ratios of thefunctional monomers, the dopant, and the cross-linker, were optimized by anorthogonal array design. The resultant sorbent was characterized by scanning electronmicroscopy, transmission electron microscopy, energy dispersed spectrum, Fouriertransform infrared spectroscopy, magnetometry, and powder X-ray diffraction. The binding performances of the sorbent were evaluated by static, kinetic and selectiveadsorption experiments. The nano-sorbent was successfully applied to solid phaseextraction followed by spectrophotometric trace determination of DMZ in feed, milkpowder, and egg samples.(2) Determination of dimetridazole using carbon paste electrode modified withaluminum doped surface molecularly imprinted polymer. An aluminum doped surfacemolecularly imprinted polymer (MIP) modified carbon paste electrode (MIP-CPE)was developed for the trace detection of dimetridazole in food and feed samples usingdifferential pulse stripping voltammetry. The component and morphology of the MIPwere characterized by transmission electron microscopy and the performance of thedeveloped MIP-CPE was investigated by cyclic voltammetry. Simultaneously, variousfactors were optimized and studied in the work, which were known to affect thesensor’s response. Because of the aluminum doping, the imprinted sensor exhibitsvery high recognition ability and affinity for DMZ in comparison with the aluminumfree MIP–CPE and the non-imprinted one. The sensors have been used for thedetermination of dimetridazole in feed, milk powder, and eggs samples and validatedby HPLC method with good precision and accuracy. The proposed sensor displayshigh selectivity, good stability, and excellent reproducibility for the reliabledetermination of DMZ in food and feed samples, and is promising for the detection ofdimetridazole in food and other related products as a routine method in future.