Tris(2,2'-bipyridyl)ruthenium(II)-Zirconia-Nafion composite modified electrode applied as solid-state electrochemiluminescence detector on electrophoretic microchip for detection of pharmaceuticals of tramadol, lidocaine and ofloxacin.

Tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+))-Zirconia-Nafion composite modified glassy carbon disk electrode as a solid-state electrochemiluminescence (ECL) detector is successfully applied to an electrophoretic microchip system with a wall-jet configuration. Pharmaceuticals such as tramadol, lidocaine and ofloxacin were selected to characterize the performance of this microchip capillary electrophoresis (CE)-ECL detection system. Voltammetric and ECL behaviors of immobilized Ru(bpy)(3)(2+) were investigated in lidocaine system. Influences of the separation electric field to cyclic voltammograms (CVs) of the immobilized Ru(bpy)(3)(2+) were also investigated. Tramadol, lidocaine and ofloxacin can be baseline separated without any additives. The detection limits (S/N=3) were 2.5x10(-5)molL(-1) for tramadol, 5.0x10(-6)molL(-1) for lidocaine, 1.0x10(-5)molL(-1) for ofloxacin under the sample injection of picoliters, and the linear ranges were from 5.0x10(-5) to 2.5x10(-3)molL(-1) for tramadol, 1.0x10(-5) to 1.0x10(-3)molL(-1) for lidocaine, and 1.0x10(-5) to 2.5x10(-3)molL(-1) for ofloxacin, respectively.