Mixed mode monolithic sorbent in pipette tip for extraction of ractopamine and clenbuterol prior to analysis by HPLC-UV and UHPLC-Q ExactiveTM Plus Orbitrap MS

Abstract This work developed a fast and simple method for the quantification of two important ?-agonists, ractopamine (RAC) clenbuterol (CLEN) in animal urines. The was based on micro-extraction by mixed mode monolithic material analysis HPLC-UV UHPLC-Q Exactive TM Plus Orbitrap mass spectrometer. A functional monolith with nonpolar ester-based structure containing polar carboxylic groups thermally synthesized situ pipette tips. combines both hydrophobic ionic interactions. Parameters including conditions composition reagents in-pipette tip synthesis, as well extraction process, were investigated optimized. procedure is 800 ?L washing solvent 10:90 ( v/v ) ACN:water 150 eluting 30:70 ACN:200 mM acetate buffer pH 4.0. Extraction efficiencies 92% 100% RAC CLEN, respectively, achieved within 5 min total organic consumption 395 ?L. extracts spiked cattle swine urines analyzed Good recovery acceptable precision observed. spectrometry data confirmed efficient matrix removal sorbent allowing routine method.