Application of dual-template molecularly imprinted polymer-based solid phase extraction for determination of phenothiazines and benzodiazepines in swine feed

Abstract

In this study, a novel dual-template molecularly imprinted polymer capable of simultaneously recognizing 4 phenothiazines and 5 benzodiazepines was synthesized. From the comparison of the 3D conformations of the two templates and the analytes, it was concluded that the shapes and sizes of the templates used in this study influenced the polymer's recognition ability. The polymer was used to prepare a solid phase extraction cartridge, which was used to purify the extract of the swine complete formula feed sample obtained with 10 mL acetonitrile/0.1% formic acid (3 : 7, v/v). The results were determined using ultra performance liquid chromatography. During the experiments, the flow rate, loading solvent, washing solvent and eluting solvent were optimized. The limits of detection for the 9 drugs were in the range of 1.5–10 ng g⁻¹, and the recoveries from the fortified blank feed samples were in the range of 85.6–97.9%. This is the first study reporting the use of a molecularly imprinted polymer-based extraction method for determining the two classes of sedatives in animal feed.