Preparation Of Immunomagnetic Beads And Their Application In Detecting Aflatoxin B₁in Vegetable Oil

Vegetable oil, an extensively consumed commodity among Chinese consumers, is a necessityfor human life. As such, vegetable oil safety is of great significance not only because of humanhealth protection, but also the overall growth of trade and maintenance of socio-economicdevelopment. Mycotoxin contamination in the raw materials of vegetable oils has become an bigsecurity risks for edible vegetable oil, and so the detection of aflatoxin in vegetable oil seems to bevery important.Immunomagnetic beads purification as a means of pre-treatment for the detection of aflatoxinB₁in vegetable oil can avoid many weakness of the traditional methods, and HPLC at the same timecan improve the signal to noise ratio, detection accuracy and can decrease the detection time at thesame time, which achieve the quest for accurate quantification, quick and easy protocol withimproved efficiency. In this study, two kind of immunomagnetic beads prepared by chemical andbiological methods respectively were used to detect the aflatoxin B₁in vegetable oil and achievedremarkable effect.The main results and conclusions obtained in this study are as follows:1. A kind of super paramagnetic nanoparticles with the key component Fe₃O₄was prepared bythe method of chemical co-precipitation. The surface hydroxyl of the magnetic beads could reactwith the silane coupling agent aminopropyltriethoxysilane and make them with amino groups. Afteractivated with the agent glutaraldehyde, the magnetic beads couple with aflatoxin B₁polyclonalantibody to form the immunomagnetic beads.2. A micro-aerobic bacteria—magnetotactic bacteria which move along the magnetic line offorce was isolated from the sediment of Wuxi Taihu lake. After enrichment and growth of thebacteria, one kind of magnetic nanoparticles-magnetosomes were produced from the bacterial bodywith the average size about15nm. The functional immune magnetosomes can be obtained bycoupling the magnetosomes with antibody through the coupling agent carbodiimide.3. A method was established afterward to detect the aflatoxin B₁in vegetable oil by using theorganic solvent for preliminary extraction, the aflatoxin B₁immunomagnetic beads system to purifyand HPLC to quantify. The method showed good linearities in the range of2⁵0ng/mL withcorrelation coefficient of0.9993and detection limit of0.5ng/mL. The recovery of the methodusing the Fe₃O₄immunomagnetic beads to purify is up to73.1%⁸2.9%and the magnetosomeimmunomagnetic is up to87.5%⁹3.1%. Besides, the detection process can be finished within30minutes, which showed a rapid, simple and high accuracy characteristic.