Study On The Technique For Residues Analysis Of Nitrofuran

In this study,molecularly imprinted polymers with specific recognition properties for semicarbazide and 1-amino-hydantoin were prepared by the method of bulk polymerization,using molecular imprinting technique.The binding capacity was studied by equilibrium binding test.MIP was used as solid-phase extraction sorbent for the preparation of solid-phase extraction column to separate and concentrate trace of nitrofuran in the determination process of trace residues of nitrofuran antibiotics in foods derived from animals,with the merits such as:less interference and convenient analysis, and the three disadvantages of low actual recovery of analyte,significant matrix interference and the low column life was avoided in the determination process of trace residues of nitrofuran antibiotics in foods derived from animals.There are four chapters in this study.Chapter one,the nature of nitrofuran drug,the principle of molecular imprinting technique,application of this technique and its prospect were introduced.Chapter two,a series of polymers were prepared in different solvents using semicarbazide,methacrylic acid and ethylene glycol dimethacrylate as the template molecular,functional monomer and cross-linker,respectively.The effects of the composition of polymerization systems on the adsorption property of MIP were investigated by static equilibrium binding test.The result indicated that the best adsorption property between MIP and template was obtained in the following conditions:the molar ratio of template molecular to functional monomer was 1:4,and the solvent was CH₃OH-CH₃CN(1:1 in volume).Scatchard analysis indicated the imprinted polymer using methacrylic acid as functional monomer could form one kind of binding site by noncovalent interactions and its dissociation constant was 1.44mmol/L.Chapter three,MIP was prepared under different ratios between template molecular and functional monomer.MIP was synthesized by the method of bulk polymerization, using AHD,MAA and EDMA as template molecular,functional monomer and cross-linker,respectively,and the absorption ability of MIP on template molecular was studied.Scatchard analysis also indicated the imprinted polymer using methacrylic acid as functional monomer could form one kind of binding site by noncovalent interactions and its dissociation constant was 4.33mmol/L.Chapter four,molecularly imprinted polymers was used both for the preparation of solid-phase extraction column,and sample pre-treatment.Residues of nitrofuran antibiotics in foods derived from animals were tested by reverse phase high performance liquid chromatography.These results showed that the linear ranges of semicarbazide and 1-amino-hydantoin were 1μg/mL～200μg/mL and 0.5μg/mL～200μg/mL,respectively,the linear correlation coefficients were r=0.9991 and r=0.9987,respectively.In three adding concentrations:1.0μg/g,5.0μg/g,50.0μg/g,the average recoveries for these two kinds of metabolites were in the range of 81.0%and 85.5%,and the relative standard deviations (RSD) were in the range of 1.98%and 5.01%(n=6).