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Spectroelectrochemical Sensor for Spectroscopically Hard‐to‐detect Metals by in situ Formation of a Luminescent Complex Using Ru(II) as a Model Compound
Author(s) -
Lines Amanda M.,
Warner Joshua D.,
Heineman William R.,
Clark Sue B.,
Bryan Samuel A.
Publication year - 2018
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201800427
Subject(s) - ruthenium , luminescence , redox , chemistry , metal ions in aqueous solution , electrochemistry , quantum yield , photochemistry , selectivity , aqueous solution , metal , ligand (biochemistry) , spectroscopy , ion , absorption spectroscopy , absorption (acoustics) , detection limit , bipyridine , inorganic chemistry , materials science , electrode , fluorescence , optoelectronics , catalysis , organic chemistry , biochemistry , physics , receptor , quantum mechanics , composite material , chromatography , crystal structure
Fast, robust, and cost‐effective means of detecting spectroscopically inactive metal species are necessary for field detection and applications within a variety of areas including industry and the nuclear safeguards fields. A sensor based on spectroelectrochemistry is an excellent candidate to meet these needs as it provides improved selectivity for specifically quantifying metal ions by simultaneously monitoring at least two physio‐chemical properties. Ruthenium was chosen as a model system for this study due to its spectroscopic and electrochemical characteristics as well as its relevance within the fuel cycle and industrial fields. Aqueous Ru displays multiple redox couples in which all available oxidation states have poor sensitivity for detection by visible absorption spectroscopy because of the low molar absorptivities. Ru can, however, form complexes with sensitizing ligands such as 2,2′‐bipyridine, where the resulting [Ru(ligand) 3 ] 2+ complex displays a red luminescence with a high quantum yield of emission. This significantly improves detection limits for Ru and allows for the spectroelectrochemical detection of the otherwise hard‐to‐detect metal ion. This work explores the in‐situ generation of Ru(bpy) 3 complexes in simulated field samples and their subsequent spectroelectrochemical sensing using our sensor methodology.