Tris(2,2'-bipyridyl)ruthenium(III)-based electrochemiluminescence detector with indium/tin oxide working electrode for capillary electrophoresis.
A novel tris(2,2'-bipyridyl)ruthenium(III) [Ru(bpy)3(3+)]-based electrochemiluminescence (ECL) detector for capillary electrophoresis (CE) has been developed. The detector was of the wall-jet configuration and an indium/tin oxide (ITO)-coated glass plate was used as the working electrode for end-column detection. Potential control of the ITO electrode was provided using a DC battery, without decoupling the detector from the CE field. Electrochemical behavior of Ru(bpy)3(2+) at the ITO electrode was found to be analogous to that at a Pt electrode. In the presence of tertiary or some secondary amines, ECL emission due to reaction between in situ generated Ru(bpy)3(3+) and analytes can be observed at the ITO surface. With 15 mM sodium borate (pH 9.5) plus 1 mM Ru(bpy)3(2+) present in the detection cell and the ITO electrode biased at 1.5 V (vs. Pt wire reference), a detection limit of 1 microM proline with a theoretical plate number of 4000 was obtained using the developed CE-ECL detection system. The detector response was found to be analyte-dependent, e.g. tryptophan gives no response, and the response for histidine is about 13-fold lower than that of proline.
Chiang
M T
MT
Department of Chemistry, Tunghai University, Taichung, Taiwan.
Whang
C W
CW
D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation*; D019075:Electrophoresis, Capillary / Q000295:instrumentation*; D007204:Indium / Q000737:chemistry*; D008163:Luminescent Measurements; D009942:Organometallic Compounds / Q000737:chemistry*; D017971:Tin Compounds / Q000737:chemistry*
D009942:Organometallic Compounds; D017971:Tin Compounds; D007204:Indium; C058901:tris(2,2'-bipyridine)ruthenium III; D015082:2,2'-Dipyridyl; C045358:stannic oxide