Polyethyleneimine-modified hybrid silica sorbent for hydrophilic solid-phase extraction of thyreostats in animal tissues.

In this work, a novel polyethyleneimine-modified hybrid silica material was developed and utilized as a solid support for hydrophilic solid-phase extraction (HILIC SPE) of thyreostats in animal tissue samples. The effects of critical parameters of extraction, including acetonitrile content, pH, sample loading volume, elution volume, sample loading flow rate and elution flow rate were completely optimized. It was found that the polyethyleneimine-modified hybrid silica sorbent displayed a high adsorption capacity of 15.8 mg/g, and the breakthrough volume was up to 40 mL. The proposed HILIC SPE method provided low detection limits of 0.5-2.2 μg/kg, and excellent recoveries of 93.4-103.1% with relative standard deviations of 3.6-9.6% (n = 3). Importantly, compared with the traditional clean-up methods for determination of thyreostats in complex matrices, the developed HILIC SPE method eliminated drying and redissolving steps. In the further, the proposed HILIC SPE method is expected to be widely applied for the clean-up of small polar and hydrophilic compounds in complex matrices.