Determination of Atenolol and Metoprolol by Capillary Electrophoresis with Tris(2,2′-bipyridyl)ruthenium(II) Electrochemiluminescence Detection

Capillary electrophoresis (CE) coupling with a tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)32+) electrochemiluminescence (ECL) detection technique was developed for the analysis of two β-blockers, atenolol (AT) and metoprolol (ME). The parameters that influence the separation and detection, including the buffer pH and concentration, the separation voltage, the detection potential and Ru(bpy)32+ concentration, were optimized in detail. The calibration curve was linear over a concentration range of two or three orders of magnitude for the two β-blockers. The detection limits for AT and ME were 0.075 and 0.005 μM (S/N = 3). The relative standard deviations (n = 8) of the ECL intensity and the migration time were 2.65 and 0.22% for AT, 2.82 and 0.34% for ME, respectively. The proposed method was applied to determine AT and ME in spiked urine samples; satisfactory results were obtained.