Single click synthesis of a mixed-mode silica sorbent and application in matrix solid-phase dispersion extraction of β-agonists from porcine liver

A single click strategy is proposed for the preparation of a reversed-phase/weak cation-exchange silica-based sorbent (silica-WCX). Upon this strategy, both 1-dodecyne and 5-hexynoic acid were simultaneously immobilized onto azide-silica in varied ratio via Cu (I)-catalyzed azide-alkyne cycloaddidon click reaction. The chemical compositions of silica-WCXs were characterized by elemental analysis, acid base titration and Fourier transform-infrared spectroscopy. The results indicated that the actual mole ratio of n-dodecyl to carboxylic group on the sorbent is almost the same as the reactant ratio of 1-dodecyne to 5-hexynoic acid, and the repeatability of synthesis method is good. After that, two beta-agonists, clenbuterol and ractopamine, were selected as model drug residues to evaluate the applicability of silica-WCX in matrix solid-phase dispersion extraction for the determination of basic drug residues in porcine liver by HPLC/UV. In comparison with some commercial sorbents, silica-WCX exhibited higher recoveries and better purification capability. Under the optimized conditions, linearity ranges were between 0.04 and 8.0 mu g/g for both analytes with coefficients of determination (R-2) higher than 0.9997. The average recoveries at three spiked levels ranged from 92.5% to 105.0% with RSDs less than 6.6%. (C) 2014 Elsevier B.V. All rights reserved.