Stopped-flow analysis of Ru(bpy)33+chemiluminescent reactions

Abstract

The stopped-flow technique was employed to measure chemiluminescent emission from the reaction of a mixture of oxalate and proline with a chemiluminescence reagent, tris(2,2'-bipyridine) ruthenium(III), or Ru(bpy)3(3+) is a versatile reagent and is often used in bioanalytical applications, including the detection of certain drugs and their metabolites, for example. Unfortunately, Ru(bpy)3(3+) has not yet been fully examined as a possible chemiluminescence reagent for simultaneous kinetic determinations. In this work, a differential reaction rate method, based on simple least squares regressions of the pseudo-first order decay data, was used to resolve two compounds, oxalate and proline, reacting simultaneously with Ru(bpy)3(3+). Our results indicate that stopped-flow analyses with Ru(bpy)3(3+) could provide a viable method for simultaneous determinations of unresolvable analytes of environmental and pharmaceutical importance.

Long‐lived electrochemiluminescence of ruthenium (II) complexes/tri‐n‐propylamine in aqueous solutions

“…Equations 4 and 6 demonstrate two approaches to reduce Ru(bpy) 3 3+ . As mentioned before, a slow reaction between Ru(bpy) 3 3+ and TPA was evidenced in CL measurements over a time scale of seconds . This finding seems to suggest a comparable life time of Ru(bpy) 3 3+ in our system, but this is not the case.…”

“…In addition to Wightman's study, we also noticed that emission decayed over a seconds time scale in the chemiluminescence (CL) reactions between Ru(bpy) 3 3+ and a number of coreactants. [20] While the longest-lived emission was found in the Ru(bpy) 3 3+ /proline system with a half-life time τ 1/2 = 22.9 sec, the Ru(bpy) 3 3+ /TPA system also exhibited a long-lived emission with a τ 1/2 = 5.2 sec. [20] But again, these CL reactions were performed under quite different conditions, in which Ru(bpy) 3 3+ was about 1 mM and in excess of that required for stoichiometric reaction with each coreactant.…”

“…[20] While the longest-lived emission was found in the Ru(bpy) 3 3+ /proline system with a half-life time τ 1/2 = 22.9 sec, the Ru(bpy) 3 3+ /TPA system also exhibited a long-lived emission with a τ 1/2 = 5.2 sec. [20] But again, these CL reactions were performed under quite different conditions, in which Ru(bpy) 3 3+ was about 1 mM and in excess of that required for stoichiometric reaction with each coreactant. Furthermore, in these CL experiments, the co-reactants had not undergone heterogeneous oxidation before they participated in the reactions with the electrogenerated Ru(bpy) 3…”

“…The long life time of Ru(bpy) 3 3+ is well known as the redox wave of Ru(bpy) 3 2+/3+ is reversible, not only in nonaqueous and but also in aqueous buffers, and because Ru(bpy) 3 3+ could be electrogenerated and kept in aqueous solutions for some time before a CL reaction . However, it reacts with reducing agents at different rates.…”

“…could be electrogenerated and kept in aqueous solutions for some time before a CL reaction. [20,26] However, it reacts with reducing agents at different rates. Equations 4 and 6 demonstrate two approaches to reduce Ru(bpy) 3…”