Preparation of Tetracycline Surface Molecularly Imprinted Material for the Selective Recognition of Tetracycline in Milk

Silica particles were modified with 3-methacryloxypropyl trimethoxysilane (MPS) as a carrier material. The tetracycline (TC) molecular imprinting polymer based on the surface of modified silica (MPS/SiO2) was prepared by adopting the novel surface molecular imprinting technique with tetracycline as template molecule and ethylene glycol diglycidyl ether (EGDE) as crosslinker. The rebinding capacity of molecularly imprinted polymer (MIP) was evaluated according to the adsorption kinetics and the adsorption isotherm. The two distinct linear portions in Scatchard analysis indicate that two classes of binding sites existed in the imprinted polymer. The MIP obtained was used as a selective sorbent for molecularly imprinted solid-phase extraction (MISPE) prior to HPLC analysis. The results showed that good linearity was observed in the range of 150∼950 μg/L for TC, with a correlation coefficient of 0.9972. Adding level of 300∼700 μg/L, the average of spiked recoveries of TC is about 81.1 %, with a relative standard deviation (RSD) range from 3.0 to 4.4 %, and the limit of detection (LOD) reached 25 μg/L. The proposed method is easy to operate, reliable, and applicable to analyze the TC residues in milk samples.