Evaluation of Use of Tris(2,2'-bipyridyl)ruthenium(III) as a Chemiluminescent Reagent for Quantitation in Flowing Streams

Abstract

Three approaches are comparatively evaluated for the use of tris(2,2'-bipyridyl)ruthemum(II), Ru(bpy)33+, as a chemiluminescent reagent in flowing streams: (1) external generation of the reactive Ru(bpy)33+ oxidation state followed by contact with the analyte, (2) in situ generation of the Ru(bpy)33+ species from a solution mixture of the analyte and the Ru(bpy)32+ species as it passes through the reaction/observation cell, and (3) in situ generation of the Ru(bpy)33+ species from the Ru(bpy)32+ species immobilized within the observation cell. Oxalate and proline were used as representative analytes for comparison of these three modes with respect to the influence of experimental variables (reagent concentration, flow rate, pH) and resulting analytical performance (detection limit, working range, measurement precision). Additionally, a comparison was made of the relative ECL intensities obtained for a variety of analytes including oxalate, amino acids, aliphatic amines, peptides, and NADH. We find that each approach has its unique set of strengths and weaknesses. The external generation mode yields the most intense emission, especially for simple aliphatic amines, but working curves have poor linearity, and emission intensities have a large dependence on solution flow rate. The in situ immobilized approach results in lower intensities but yields the widest linear dynamic ranges, is most conservative of reagent, and has a particular sensitivity advantage for proline and NADH determinations. The in situ solution mode is superior for the detection of amino acids such as tryptophan, 5-hydroxytryptophan, and histidine and has time, convenience, and reliability advantages.In recent years, tris(2,2'-bipyridyl)ruthenium(III) electrogenerated chemiluminescence (ECL) has received considerable attention in chemical analysis because of its utility for detection of alkylamines, amino acids, and NADH without derivatization.Several research groups have been actively investigating the ECL mechanism of Ru(bpy)32+ and its analytical applications. Bard and co-workers have reported a series of investigations on the

Preparation of Nafion-Ru(bpy)32+-Chitosan/Gold Nanoparticles Composite Film and Its Electrochemiluminescence Application

“…However, because of the instability at positively biased potentials and possible desorption in organic solvent, these techniques cannot be applied widely. Moreover, the incorporation of Ru(bpy)3 2+ within perfluorosulfonated ionomer Nafion films 16,17 had received considerable attention. Such an ECL sensor was used not only for the determination of oxalate, amines, NADH, and antibiotics, but also for the enzymatic biosensors to determine glucose or ethanol.…”

Chemiluminescence Determination of Thiourea Using Tris(2,2′-bipyridyl)ruthenium(II)–KMnO4 System

“…The CL method has been widely used because of its high sensitivity and simplicity. Ru(bipy) 3 2+ is a widely used electrogenerated CL reagent 13 and has become a useful CL reagent. It has been used for the determination of some organic acids in the Ru(bipy) 3 2+ -Ce(IV) chemiluminescence system.…”

Advances and analytical applications in chemiluminescence coupled to capillary electrophoresis

“…Solvents usually applied in CL determinations based on these reactions include ACN-water, methanol-water and acetone-water [19]. Extensive reviews have summarized the analytical usefulness of RuðbpyÞ 21 3 as an ECL label [20][21][22][23][24] or some advances in relation to the use of ECL on microfluidic chips [25,26]. RuðbpyÞ 21 3 is the stable species in the solution.…”