Abstract:

Objective: To establish a new method for the effective separation and sensitive detection of four fluorouinolones (ofloxacin, norfloxacin, ciprofloxacin and enrofloxacin) residues in chicken by using molecularly imprinted solid phase extraction-HPLC. Methods: Water-compatible molecularly imprinted polymers (MIPs) were synthesized in methanol-water systems with enrofloxacin as templates and methacryclic acid as functional monomers, and their characteristics were investigated and evaluated. The chicken samples were extracted with acetonitrile, purified by molecularly imprinted solid-phase extraction column with mixture of acetonitrile and trifluoracetic acid (99:1, V/V) as elution solution, and then the eluent was separated by HPLC and detected by fluorescence method. Results: The MIPs have good adsorption specificity to six fluoroquinolones. For the higher affinity site, Kd1 is 7.19×10-5  mol/L, and Qmax,1 is 110.19  μmol/g; For the lower affinity site, Kd2 is 2.44×10-3  mol/L, and Qmax,2 965.51 μmol/g. Excellent linear relationships may be obtained in the range of 1.0 to 500 μg/kg (r ≥ 0.9991). The determination limits (S/N= 3) are in the range of 0.06 to 0.09  μg/kg. The mean recoveries range from 75.3% to 88.5% with relative standard deviations below 6% (n = 3). Conclusion: The effective separation and sensitive detection of the four fluorouinolones in chicken can be archived by using the water-compatible molecularly imprinted solid phase extraction-HPLC.

Key words: molecularly imprinted polymers, solid-phase extraction, HPLC, fluoroquinolones, chicken