Role of electron-donating/withdrawing character, pH, and stoichiometry on the chemiluminescent reaction of tris(2,2'-bipyridyl)ruthenium(III) with amino acids

Abstract

A postcolumn chemiluminescent technique for the detection of underivatized amino acids using electrogenerated tris-(2,2'-blpyrldyl)ruthenlum( 111) is described. The reaction chemistry has been investigated, and It has been shown that the electron-withdrawing/donating character of the R group attached to the -carbon of the amine Influences the chemiluminescent efficiency of the reaction. Stoichiometric studies conducted on four amines produced a mole ratio of 2:1, ruthenlum:amlne. At optimum reaction conditions the relative intensities of the primary amino acids tested varied by a factor of 55, with serine yielding the lowest chemiluminescence and leucine yielding the highest chemiluminescence. Detection limits for serine and leucine have been calculated to be 135 and 3 pmol, respectively, at a S/N of 3. Linearity has been demonstrated over 2 orders of magnitude for Leu. The ability to implement this system for postcolumn chemiluminescence detection of amino acids following a protein digest has been demonstrated.

The influence of poly(2-methoxyaniline-5-sulfonic acid) on the electrochemical and photochemical properties of a highly luminescent ruthenium complex

“…These properties uniquely enable the development of advanced diagnostic devices based on the luminescent detection of analytes including proteins and DNA biomarkers since more rapid electrochemical production of the Ru 3+ state ought to produce a greater total emission intensity per unit time [14]. ECL represents a powerful analytical approach that combines simple equipment with inherent sensitivity, selectivity, and a wide linear dynamic range for amine containing analytes, such as alkylamines, NADH, hydrazine, amino acids, biomolecules and a variety of pharmaceutical compounds [15][16][17][18][19]. ECL usually involves the reaction of electrogenerated species that react to form excited states, usually via an energetic redox reaction [19].…”

Determination of Atenolol and Metoprolol by Capillary Electrophoresis with Tris(2,2′-bipyridyl)ruthenium(II) Electrochemiluminescence Detection

“…The electrogenerated Ru(bpy)3 3+ was the stoichiometrically limiting reagent for the ECL reaction (Ru(bpy)3 3+ :amine = 2:1). 45 Therefore, increasing the concentration of Ru(bpy)3 2+ resulted in an increased concentration of Ru(bpy)3 3+ , and thus an increased ECL intensity. However, the background noise increased with increasing Ru(bpy)3 2+ concentration.…”

“…The ECL intensity produced by ME was constantly larger than that of AT under the same conditions. The Bobbitt group 45 has investigated the effect of R groups attached to the α-carbon of the amine group on the Ru(bpy)3 2+ ECL intensity. In general, it has been found that electron-withdrawing groups tend to decrease the ECL intensity and that electron-donating groups increase the ECL intensity.…”

Electrochemiluminescence Sensor for the Detection of Tiapride Hydrochloride with Chitosan-Ru(bpy)32+-SiO2NPs/MCNT/Nafion Modified Electrode

“…It was reported that tertiary amines were easier to oxidize because of their lower ionization potentials originating from electrons in the nitrogen orbitals, and within the group of tertiary amines, the ionization potential decreased when the length of the alkyl chain increased, 19 the electron donating effected the emission intensity as they react with [Ru(bpy) 3 ] 3+ . 20 It was well known that tri-n-propylamine (TPrA) may serve as the co-reactants for [Ru(bpy) 3 ] 2+ ECL reaction, as well as a wide range of amine compounds.…”