Electrocatalysis at a conducting composite electrode doped with a ruthenium(II) metallodendrimer.
A pentaerythritol-based metallodendrimer with RuIIterpyridine units was synthesized and tested as a mediator for the electrochemical oxidation of methionine (L-Met), cystine (L-Cys), and AsIII. A reversible oxidation of RuII was observed with the metallodendrimer as a solute in mixed acetonitrile-water solvents and as a component of carbon-based conducting composite electrodes. Mediated oxidation of the test species was observed. In aqueous solution, the composite electrode yielded a cyclic voltammetric peak current for the oxidation of L-Met in a 0.1 M phosphate buffer (pH 7.0) at 1.1 V vs Ag/AgCl. This anodic process was employed for amperometric detection in a flow system. Linear calibration curves were obtained over the range 1.0-10 microM Met and Cys. Using the criterion of the concentration yielding a signal 3 times the uncertainty of a blank, detection limits of 0.6 and 0.5 microM were calculated for Met and Cys, respectively. The slopes with three nominally identical electrodes varied by 10%.
Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, USA.
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D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000737:chemistry; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D004566:Electrodes; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009942:Organometallic Compounds / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry
D009942:Organometallic Compounds; D011506:Proteins; C095932:chloro(2,2'-6',2''-terpyridine)(2,2'-bipyridine)ruthenium; D015082:2,2'-Dipyridyl; D012428:Ruthenium