title: Self-quenching in the electrochemiluminescence of tris(2,2'-bipyridyl) ruthenium(ii) using metabolites of catecholamines as co-reactants.
abstract: Electrochemiluminescence (ECL) of Ru(bpy)(3)(2+) using metabolites of catecholamines: homovanillic acid (HVA) and vanillylmandelic acid (VMA) as co-reactants were investigated in aqueous solution for the first time. When HVA and VMA were co-existent in the buffer solution containing Ru(bpy)(3)(2+), ECL peaks were observed at a potential corresponding to the oxidation of Ru(bpy)(3)(2+), and the ECL intensity was increased noticeably when the concentrations of HVA and VMA were at lower levels. The linear calibration range was from 8.0 × 10(-5) to 1.0 × 10(-9) M for HVA and VMA. The detection limit (S/N = 3) of HVA and VMA was 4.0 × 10(-10) M. The formation of the excited state Ru(bpy)(3)(2+*) was confirmed to result from the reaction between Ru(bpy)(3)(3+) and the intermediates of HVA or VMA radicals. Moreover, it was found that the ECL intensity was quenched significantly when the concentrations of HVA and VMA were relatively higher. The mechanism of self-quenching processes involved in the Ru(bpy)(3)(2+)-HVA and -VMA ECL systems are proposed in this study.
authors.affiliation: Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou, 730070, China. taaluxq@gmail.com
authors.forename: Xiaoquan
authors.initials: X
authors.lastname: Lu
authors.forename: Haifeng
authors.initials: H
authors.lastname: Wang
authors.forename: Jie
authors.initials: J
authors.lastname: Du
authors.forename: Baomei
authors.initials: B
authors.lastname: Huang
authors.forename: Dong
authors.initials: D
authors.lastname: Liu
authors.forename: Xiuhui
authors.initials: X
authors.lastname: Liu
authors.forename: Huixia
authors.initials: H
authors.lastname: Guo
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Xue
mesh_terms: D002021:Buffers; D002395:Catecholamines / Q000737:chemistry / Q000378:metabolism*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D006719:Homovanillic Acid / Q000737:chemistry* / Q000378:metabolism; D008163:Luminescent Measurements / Q000295:instrumentation / Q000379:methods*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D014642:Vanilmandelic Acid / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002021:Buffers; D002395:Catecholamines; D009942:Organometallic Compounds; C415768:tris(2,2'-bipyridyl)ruthenium(II); D014642:Vanilmandelic Acid; D006719:Homovanillic Acid