Preparation And Application Of Molecularly Imprinted Ploymer For Selective Recognition Of Azo-Dye Orangeâ…¡

Azo-dye acid orange II possesses characteristics such as bright color, good dyeing stability, low price, non-decomposition fade, and excellent solubility. Some illegal pedlar add acid orange Ⅱ in food in the process of dyeing, which seriously harmed the consumers’ health, caused food poisoning. Exposing to the environment with acid orange Ⅱ for a long time can lead to carcinogenic, teratogenic and mutagenic effect. It is a medium carcinogen, forbidden to add in food processing.In this article, MIP nanoparticles were synthesized using a semi-covalent method, based on a thermally reversible bond. The combination of 3-(triethoxysilyl)propyl isocyanate(TEPIC) and azo-dye acid orange Ⅱ was covalent, the products were compounded to the magnetic nanoparticles coated by silicane to form Azo-dye orange Ⅱ-imprinted polymers, then a simple thermal reaction was carried out to remove the template and left the non-covalent bond for re-recognition. The synthesis factors were controlled and optimized, tested by static, kinetic and selective adsorption. The results of adsorption experiments illustrated that the imprinted polymer had fast mass transfer rate (the adsorption equilibrium was achieved in 20 min) and high saturated adsorption capacity (Qmax=64.31 mg g-1) for the template. Both MIPs and NIPs were charactered by FT-IR(4000-400 cm-1)SEM and TEM spectra for its structure confirmed, and MIP nanoparticles were applied to solid-phase extraction (SPE).A method was developed with MIP as a selective enrichment sorbent in an online solid phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC) to detect acid orange Ⅱ in environmental and food samples. The waste water sample was first implemented by procedure of magnetic MISPE. For all samples detecting by HPLC with UV/vis detection and preconcentrated by SPE pre-column, the enhancement factor got to 710.The limit of detection (S/N=3) for samples is 9.83 ng L-1,obtained a relative standard deviation(RSD,%) of 6.72%,and the linear range of calibration graph was 0.08-12.5μg L-1 (r2>0.99).At last, the three samples:waste water,red pepper powder and cured meat determined to be free of template acid orange Ⅱ, were spiked with three levels of 5.0 ng g-1,10.0 ng g-1 and 15.0 ng g-1 and analyzed after simple pretreatment.With recoveries ranged from 72%-106%,RSD of 9.89%,the new MIP-SPE-HPLC method was successfully applied to the quantification of trace acid orange Ⅱ.