A novel dual-function molecularly imprinted polymer on CdTe/ZnS quantum dots for highly selective and sensitive determination of ractopamine.

A novel dual-function material was synthesized by anchoring a molecularly imprinted polymer (MIP) layer on CdTe/ZnS quantum dots (QDs) using a sol-gel with surface imprinting. The material exhibited highly selective and sensitive determination of ractopamine (RAC) through spectrofluorometry and solid-phase extraction (SPE) coupled with high performance liquid chromatography (HPLC). A series of adsorption experiments revealed that the material showed high selectivity, good adsorption capacity and a fast mass transfer rate. Fluorescence from the MIP-coated QDs was more strongly quenched by RAC than that of the non-imprinted polymer, which indicated that the MIP-coated QDs acted as a fluorescence sensing material could recognize RAC. In addition, the MIP-coated QDs as a sorbent was also shown to be promising for SPE coupled with HPLC for the determination of trace RAC in feeding stuffs and pork samples. Under optimal conditions, the spectrofluorometry and SPE-HPLC methods using the MIP-coated QDs had linear ranges of 5.00×10(-10)-3.55×10(-7) and 1.50×10(-10)-8.90×10(-8) mol L(-1), respectively, with limits of detection of 1.47×10(-10) and 8.30×10(-11) mol L(-1), the relative standard deviations for six repeat experiments of RAC (2.90×10(-9) mol L(-1)) were below 2.83% and 7.11%.