Research And Application Of The Complex Food Separation And Analysis Methods Based On Molecular Imprinting Technique

Tetracycline antibiotics (TCs) are widely used for the treatment of infectiousdiseases and an additive to animal feeds, because of their cost effectiveness andbroad-spectrum antibacterial activity. However, these antibiotics would remain inanimal body, and then enter the body through the food like meat, milk, and eggs. Theresidues may adversely affect the human health, and they may led to the drugresistance in the body which lower the the human immune system function.Molecularly imprinting technique is a new kind of technique on the basis of theinteraction between antigen and antibody in a living body. Through the interaction ofthe template molecule, functional monomers and cross-linking agent, a threedimensional space structure of the "receptor" has been synthesized. And the receptorhas a specific "memory" for the template molecule, special affinity, high selectivityand excellent molecular recognition ability. In addition, molecularly imprintedpolymer (MIP) also have many good qualities, such as stable physical and chemicalproperties, mechanical property, resistant to high temperature, high pressure, acid,alkali, the high concentration of ion and organic solvents. Moreover, the preparationprocesses of MIP are simple, and MIPs have a long service life and can be reused.In this study, we separated and enriched the tetracycline from eggs and honey bymagnetic molecularly imprinted polymers. The magnetic molecularly imprintedpolymers which showed a good selective adsorption, easy solid-liquid separation,saving energy and high efficiency, have been prepared through the magneticseparation technology and molecular imprinting technique.Combined with microwave technology and the rapid synthesis of molecularimprinting technique molecularly imprinted polymer, energy saving time.Combinedwith macroporous resin technology and molecular imprinting technique synthesis.Thisstudy has three parts development, the main work is as follows:(1) Novel magnetic molecularly imprinted polymers were prepared usingbilayer modified Fe3O4magnetite as the magnetically susceptible component,oxytetracycline and chlortetracycline as the mixed-template molecules, andmethacrylic acid as the functional monomer. The magnetic polymers were applied tothe separation of tetracycline antibiotics from egg and honey samples. The sample,polymers and extraction solvent were blending and stirring together. The extractionand clean-up procedures were carried out in a single step. The analytes can be extracted from the sample matrix to the polymers directly or through the extractionsolvent as the medium. When the extraction was complete, the polymers which hasadsorbed the analytes were easily separated from the sample matrix by an adscititiousmagnet. The analytes eluted from the polymers were determined by high liquidchromatography spectrometry. The recoveries obtained to be76.2%to95.8%withrelative standard deviations in the range of3.1–13.2%. The limit of detection was lessthan0.2ng g1. The feasibility of this method was proved by analysis of incurred eggand honey samples. Compared with classical method in which used more stepsincluding solvent extraction, centrifugation, clean-up and concentration bysolid-phase extraction, the proposed method decreased the complexity and improvedthe reliability.(2) Mcrowave technology and detection of molecular imprinting techniqueresearch: oxytetracycline and chlortetracycline as the mixed-template molecules, andmethacrylic acid as the functional monomer,microwave synthesis of molecularlyimprinted polymer,optimization molecularly imprinted polymer synthesis conditions.Study the adsorption and choice performance, selective adsorption actual samples ofthe ingredients tetracycline, Using scanning electron microscope and Fouriertransform infrared synthesis, molecularly imprinted polymer structurecharacterization. High performance liquid chromatography-ultraviolet detectionqualitative and quantitative analysis were used to the separation and enrichmentcontent. The OTC and CTC of eggs are analysed, the linear equations were Y=278.4X36.1, Y=205.2X+108.6, linear correlation coefficient0.999and0.996,respectively.(3) Synthesis Molecular imprinting composite resin and application theseparation analysis from eggs: oxytetracycline as the template molecule, andmethacrylic acid as the functional monomer, macroporous resin as the carrier,synthesis of molecularly imprinted polymer, and study the adsorption and choiceperformance, and as a solid phase extraction column packing, selective adsorptionsamples of the tetracycline composition. Using scanning electron microscope andFourier transform infrared synthesis, molecularly imprinted polymer structurecharacterization.High performance liquid chromatography-ultraviolet detectionqualitative and quantitative analysis were used to the separation and enrichmentcontent. The OTC of eggs are analysed, the linear equation is Y=206.4X-7.5, linearcorrelation coefficient of0.997.