Characters, Mechanism And Application Of Ionic Liquid In Determination Of Contaminant Residue

Food safety is a specific environmental pollution problem. There will be more incidents within food safety in our country. The detection technique of chemical contaminants in food resource is the most important mean guarantee food safety. Separation and enrichment of residues is the difficulty and emphasis of detection methods. This paper was focus onthe new green solvent ionic liquids and rapid, effective microwave assisted extraction, set up a separation and enrichment system of antibiotic and organophosphorus pesticide by ionic liquid. The system was used to detect the trace and ultra-trace antibiotic and organophosphorus pesticide in the environment samples, while the traditional detection methods is features low sensitivity, easily polluted and bad accuracy.Two classes of five types of ionic liquid were synthesized by the two-steps, one-steps and microwave assisted methods. The factors affecting the product yield such as solvent, the ratio of reactants, time of synthesis, temperature and the way power of microwave have been studied. The optimum synthetic conditions were selected with the orthogonal test. The experiment results showed that the optimal result of synthesis is obtained from reactants at molar ratio 1:2 with bromoalkane as solvent for about 30 h. The yield is about 95.91%. The microwave irradiation time last 240 s, each time last 20 s, power at 350 W. In this way the product yield was 98.72%.The hydrophobic ionic extraction system and hydrophilic ionic aqueous two-phase extraction system were established. The factors affecting the extraction yield such as dosage of ionic liquid, concentration of erythromycin, kind of inorganic salt, extraction method, time of extraction, temperature, pH have been studied, while the extraction yield of ionic liquid and organic solvent were compared. The ionic liquid can be recycling used and regenerated. The optimum synthetic conditions were selected with the orthogonal test. Under the optimum technological condition, the extraction yield of hydrophobic ionic extraction system and hydrophilic ionic aqueous two-phase extraction system were 98.61%and 99.31%, respectively.The microwave assisted extraction was used in the extraction process. The factors affecting the extraction yield such as dosage of ionic liquid, concentration of erythromycin, pH, time of microwave irradiation, time of microwave irradiation have been studied, comparison and analysis on extraction yield of two kinds of synthetic methods for ionic liquid. The microwave irradiation 3 times, each time last 20 s, power at 210 W. In this way the extraction yield was 93.27%.The extraction equilibrium constants (Kex) for [Bmim]PF6, [Pmim]BF4, [Emim]BF4 and [Bmim]BF4 have been determined at 303.15 K. According to the kinetic experimental data, the kinetic parameters and the rate equation were calculated. The thermodynamic and kinetic analysis of erythromycin extraction by ionic liquid showed that the extraction mechanism should be of ion exchange and association and extraction process accorded with the first order reaction kinetics model.Experimental results showed the organophosphorus pesticide could by extracted by ionic liquid as well. Quantitative analysis method of organophosphorus pesticide by high performance liquid chromatography using ionic liquid as extractant has been developed. The experiment results showed that with 1.5 g ionic liquid as extractant for about 40 min at room temperature. The extraction yield is about 91.58%.The determination methods of antibiotic and organophosphorus pesticide in food have been developed. This method has low detection limit, good precision and accuracy, and wide linear range; the data of accuracy and repeatability are satisfied for analysis on the trace amounts of antibiotic and organophosphorus pesticide residues.