ENROFLOXACIN-IMPRINTED MONOLITHIC HPLC COLUMNS SYNTHESIZED BY IN SITU COPOLYMERIZATION FOR CHROMATOGRAPHIC SEPARATION

Abstract

A monolithic molecularly imprinted polymer for enrofloxacin was synthesized by in situ copolymerization of methylacrylic acid and methyl methacrylate in a traditional stainless-steel chromatographic column for the rapid separation and determination of enrofloxacin and ciprofloxacin in eggs. By optimizing the polymerization condition, the monolithic MIP showed highly specific recognition for enrofloxacin over its active metabolite ciprofloxacin. The influence of components of monomers on hydrophobicity, contractibility, selectivity, and binding capacity of polymer were investigated. As shown by SEM, the mesopores and macropores were formed in the monolith column; this allowed the mobile phase to flow through the column with low backpressure. Furthermore, some chromatographic conditions such as mobile phase composition and flow rate on the retention times were investigated. The binding capacity was evaluated by static adsorption and Scatchard analysis, which showed that the dissociation constant and the maximum binding capacity were 117.7 mg/L and 27.27 mg/g for high affinity binding site, and 297 mg/L and 187.4 mg/g for lower affinity binding site, respectively. The mean recoveries of enrofloxacin and ciprofloxacin from egg samples were 103.3–115% and 89.3–95.1%, respectively. The research has shown that copolymerization provides more adjustable conditions for making molecularly imprinted monolithic columns with different morphologies and higher selectivity.

Keywords:

• copolymerization
• egg samples
• enrofloxacin imprinted polymer
• monolithic column

ACKNOWLEDGMENTS

The authors gratefully appreciate the financial support by the Hebei Provincial Key Basic Research Program (No. 10967126D), the Natural Science Foundation of Hebei Province (No. B2011201081), National Natural Science Foundation of China (No. 20675024, 20905019), Natural Science Foundation of Hebei Educational Committee (No. 2006407), and Science Foundation of Hebei University.

Notes

HPLC conditions: column size, 125 mm × 4.6 mm I.D.; column temperature, 20°C; flow rate, 0.4 mL/min; detection wavelength, 280 nm; mobile phase, chloroform-acetic acid (98:2, v/v); k ₁ and k ₂ are retention factor of the ciprofloxacin and the enrofloxacin, respectively; α is separation factors, α = k ₂ /k ₁ ; IF is imprinted factor, IF = k _imprinted/k _{non-imprinted}.