Electrochemically generated Ru(bpy)33+-based chemiluminescence detection in micellar electrokinetic chromatography
ABSTRACT In situ generated Ru(bpy)33+-based chemiluminescence (CL) detection will be shown to be compatible with micellar electrokinetic chromatography (MEKC) providing significant advantages over other Ru3+ generation protocols. The CL reagent, Ru(bpy)32+ is continuously added post-capillary to avoid precipitating the anionic surfactant used to enhance the separation of neutral analytes. Ru(bpy)33+ is then electrochemically generated in situ at the interface between the separation capillary and the working electrode, where it can react with specific analytes, for example amines and amino acids to produce chemiluminescent emission. With this scheme, the critical micelle concentration is not exceeded in the detection zone, freeing the analyte to react with the Ru(bpy)33+ CL reagent. The separation and detection of various underivatized amines will be demonstrated using this methodology. For triethylamine, 70 000 plates per meter are demonstrated with MEKC providing a limit of detection (S/N=2) of 1.5 fmol of injected mass. The experimental approach used to improve the limit of detection while maintaining high separation efficiency will be evaluated and discussed.
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ABSTRACT: This paper describe a Ru(bpy)32+ based electrochemiluminescence (ECL) method to detect procyclidine in human urine following separation by capillary electrophoresis (CE). An ECL detection cell was designed for post-column addition of Ru(bpy)32+. Parameters affecting separation and detection were optimized, leading to a detection limit of 1×10−9 mol/l in an on-capillary stacking mode. For application in urine, a cartridge packed with slightly acidic cation-exchange resin was used to eliminate the matrix effects of urine and improve the detection sensitivity. Extraction recovery was nearly 90%.Analytica Chimica Acta 01/2002; · 4.52 Impact Factor
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ABSTRACT: A novel chemiluminescence (CL) flow system for the determination of chlortetracycline is described. It is based on the direct CL reaction of chlortetracycline and [Cu(HIO6)2]5− in KOH medium. The unstable [Cu(HIO6)2]5− was on-line electrogenerated by constant-current electrolysis. The CL intensity was linear with chlortetracycline concentration in the range of 0.1–100 μg ml−1. The determination limit was 5.3×10−8 g ml−1. The whole process could be completed in 1 min. The proposed method is suitable for automatic and continuous analysis, and has been applied satisfactorily to analysis of chlortetracycline in biological fluid.Talanta 01/2002; · 3.50 Impact Factor
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ABSTRACT: A capillary zone electrophoresis with end-column electrochemiluminescence (ECL) detector was described for the determination of benzhexol hydrochloride. The detection was based on the tris(2,2′-bypyridine)ruthenium(II) [Ru(bpy)32+] ECL reaction with the analyte. Electrophoresis was performed using a 25 μm i.d. uncoated capillary. 10 mM sodium phosphate buffer (pH=8.0) was used as the running buffer. The solution in the detection cell was 80 mM sodium phosphate (pH=8.0) and 5 mM Ru(bpy)32+. A linear calibration curve of three-orders of magnitude was obtained (with a correlation coefficient of >0.999) from 1.0×10−8 to 1.0×10−5 M and the limit of detection was 6.7×10−9 M (S/N=3). This just provides an easy and sensitive method to determine the active ingredient in pharmaceutical formulations.Microchemical Journal. 01/2004;