Determination of Tramadol in Human Serum by Capillary Electrophoresis with the End-Column Electrochemiluminescence Detection

A capillary electrophoresis (CE) coupled with end-column electrochemiluminescence (ECL) detection method for the analysis of tramadol (TMD) has been investigated. ECL detection was working electrode biased at 1.2 V in a 20 mmol·L sodium phosphate buffer (pH = 8.0) containing 5 mmol·L Ru   3 bpy  (where bpy = 2,2’-bipyridyl). Linear correlation (r ≥ 0.997) between ECL intensity and drug concentration was obtained in the range 3 × 10 6 × 10 mol·L. The limits of detection (LODs) for tramadol in water was 3.012 × 10 mol·L (S/N = 3). The relative standard deviation values on peak size (10 mol·L level) and migration time for the tramadol were 4.58% and 1.39% (n = 10), respectively. Applicability of the CE-ECL method to the analysis of human serum spiked with tramadol was examined.