Separation and determination of bupivacaine in plasma by capillary electrophoresis with tris(2,2′‐bipyridyl)ruthenium(II) electrochemiluminescence detection

A new, rapid, selective and sensitive method is described for determination of bupivacaine by capillary electrophoresis coupled with tris(2,2'-bipyridyl)ruthenium(II) [Ru(bpy)(3)2+] electrochemiluminescence detection. The influence of parameters such as detection potential, Ru(bpy)(3)2+ concentration, buffer concentration and pH, injection time and separation voltage on separation efficiency and ECL peak intensity was systematically investigated. Under optimized conditions, the calibration curve was linear in the range 0.02-10 microg/mL. The RSD was 4.0% (n = 6). The detection limit was 3 ng/mL. The recoveries obtained were about 90%. This method was tested in the analysis of plasma samples taken from a rat after it had received bupivacaine injections.