Abstract:

An enrofloxacin (ENR) molecularly imprinted membrane (MIM) was prepared with a polyvinylidenedifluoride (PVDF) membrane as the carrier, ENR as the dummy template molecule, α-methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and a chloroform-methanol mixture solvent as the porogen. The MIM showed excellent selectivity, high adsorption capacity, and high adsorption rate for ciprofloxacin. Additionally, a method combining molecularly imprinted membrane extraction (MIME) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed and validated for the selective analysis of trace ciprofloxacin residue in milk samples. The sample pretreatment involved only a single step of protein precipitation. Ciprofloxacin showed good linearity in mass concentration range of 0.1-200 μg/L with a high correlation coefficient (r²>0.9996). The limit of detection (LOD, S/N=3) and limit of quantification (LOQ, S/N=10) were 0.02 μg/L and 0.1 μg/L, respectively. The relative standard deviations (RSDs) of interday and intraday precisions ranged from 3.3% to 7.9%. The ciprofloxacin recovery was in the range of 92.6%-119.1%. The results showed that the proposed method is simple and fast, with high accuracy and sensitivity, thus being suitable for the rapid detection of trace ciprofloxacin residue in milk samples.

Key words: high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), ciprofloxacin, milk, molecularly imprinted membrane, extraction