Rapid determination of β2-agonists in urine samples by microchip micellar electrokinetic chromatography with pulsed electrochemical detection

Abstract

A rapid and simple method for the determination of four β₂-agonists was developed by using microchip micellar electrokinetic chromatography (μMEKC) with pulsed electrochemical detection (PED). The effect of solution conditions, separation potential and detection waveform were optimized for both the separation and detection of β₂-agonists. Under the optimum conditions (10 mM borate at pH 10 with 20 mM sodium dodecyl sulfate (SDS), detection potential: 0.3 V, separation potential: 1200 V, injection time: 10 s) the baseline separation of the four selected compounds was achieved. Linear responses of the four β₂-agonists were obtained over a concentration range from 1.8 to 91.2 μM and limits of detection of 0.69, 0.73, 0.91 and 1.1 μM were achieved for salbutamol (SAL), terbutaline (TER), cimaterol (CIM), and ractopamine (RAC), respectively. After 30 consecutive injections, the relative standard deviations (RSD) of the response and migration time of the analytes were less than 3.9 and 1.0%, respectively. The suitability of the method was demonstrated to analyze the four β₂-agonists in the urine sample and the recoveries of analytes in the spiked urine samples were between 89.5 and 96.7%.