Catalysis

Adsorption

Polymerization

Ethylene glycol dimethacrylate

Chromatography

Molecularly imprinted polymer

Solid phase extraction

Methacrylate

Polymer

Extraction (chemistry)

Organic chemistry

Chemistry

Selectivity

Methacrylic acid

Detection limit

Sorbent

Food Chemistry

The aim of this study was to prepare molecularly imprinted polymers (MIPs) with ampicillin (AMP) and to evaluate the feasibility of these materials for being used as solid phase extraction sorbent for the selective preconcentration and determination of AMP in cow milk samples. MIPs were synthesized by bulk polymerization using methacrylic acid or methyl methacrylate as monomer and ethylene glycol dimethacrylate as cross-linker at different ratios. Characterization of the MIPs were carried out by Fourier-transform infrared spectrometry. The variables affecting the molecularly imprinted solid-phase extraction (MISPE) procedure were optimized. AMP recoveries were higher than 98%, and RSD less than 7%. A preconcentration factor of 20 was reached, which was sufficient to determine AMP at levels allowed by the EU (4 μg kg−1) in cow milk. The selectivity of the AMP-MIP was evaluated in presence of other structurally related β-lactam antibiotics (amoxicillin, oxacillin, penicillin G).

Effective determination of ampicillin in cow milk using a molecularly imprinted polymer as sorbent for sample preconcentration