Simultaneous determination of four β2-agonist residues in pig feed and urine by capillary electrophoresis with field amplified sample injection and electrochemiluminescent detection

A novel method for simultaneous determination of clenbuterol (CLB), terbutaline (TER), salbutamol (SAL), and procaterol (PRO) was proposed based on capillary electrophoretic (CE) separation and electrochemiluminescent (ECL) detection. Matrix solid phase dispersion (MSPD) and ion exchange coupled with mesoporous nanocarbon adsorption were adopted to pretreat solid and aqueous samples, respectively. The sensitivity was enhanced by about 9-fold due to the online stacking via field amplified sample injection. The conditions for CE separation and ECL detection were investigated in detail. The four β2-agonists were baseline separated under the optimum conditions within 10 min. The linear ranges were 0.25–10.00 μmol L−1 with detection limits (S/N = 3) of 0.081, 0.076 and 0.034 μmol L−1 for CLB, TER and SAL, respectively, and 0.5–20.00 μmol L−1 for PRO with a detection limit of 0.12 μmol L−1. The developed method was successfully applied to determine the four β2-agonists in real samples, offering average recoveries ranging from 88.9% to 107.1% for pig feed, and from 86.7% to 109.1% for pig urine.