| In this study, The CdTe/CdSe core-shell QDs synthesized in water, the system’s pH is11.0, the reflux time of CdTe was3h, NaBSe dropping at2.0mL min-1, Se2-/Te2-=2.0, synthesis of quantum dots with high quantum efficiency and better water-solubility. The molecular imprinted polymer (MIP) on Quantum dot surface was prepared by surface imprinting-sol-gel using3-aminopropyl triethoxysilane(APTES) as functional monomer, Tetraethoxy-silicone (TEOS) as cross-linker, Ractopamine as template molecule with the ration of1:3:3. Then isothermal adsorption curves have been drawn and adsorption kinetics experiments were carried out. The polymer was proved holding high selectivity, good adsorption capacity(13.5mg g-1)and fast mass transfer rate(the adsorption equilibrium was achieved in90min) by a series of adsorption experiments.Competitive adsorption test indicates that the surface imprinting-sol-gel molecular imprinted polymer has high selectivity on ractopamine. This study has laid a foundation for molecular imprinted polymers applied as solid phase extraction adsorbents to determinate ractopamine in biological samples.A methord for ractopamine was developed using the prepared polymer as enrichment material by combining solid phase extraction with high performance liquid chromatography. Under the optimum SPE conditions, the enrichment factor was407.17, the linear range for ractopamine was0.05-30μg L-1with R2>0.99. The RSD for six replicate determinations of RAC(1.0μgL-1)was<7.11%.The developed method was used for the determination of ractopamine residues in feedstuffs and pork, under the optimum experimental conditions, the limits of detection (signal-to-noise ratio=3) were0.302μg kg-1and0.283μg kg-1for the feedstuffs and pork, respectively. Samples were spiked with ractopamine at concentrations of1.0,2.0,4.0μg kg-1. The average recoveries ranged from83.47-90.65%for the feedstuffs and74.61-89.23%for the pork, and the relative standard deviations (n=3) was<7.88%. |
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