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Assessing a Spectroelectrochemical Sensor’s Performance for Detecting [Ru(bpy) 3 ] 2+ in Natural and Treated Water
Author(s) -
Abu Eme A.,
Bryan Samuel A.,
Seliskar Carl J.,
Heineman William R.
Publication year - 2012
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.201200143
Subject(s) - ruthenium , analyte , tap water , analytical chemistry (journal) , absorbance , chemistry , electrode , indium tin oxide , nafion , selectivity , polystyrene , electrochemistry , materials science , inorganic chemistry , chromatography , organic chemistry , polymer , environmental engineering , engineering , catalysis
A spectroelectrochemical sensor that combines three modes of selectivity in a single device was evaluated in natural and treated water samples using tris‐(2,2′‐bipyridyl) ruthenium(II) dichloride hexahydrate, [Ru(bpy) 3 ] 2+ , as a model analyte. The sensor was an optically transparent indium tin oxide (ITO) electrode coated with a thin film of partially sulfonated polystyrene‐ block ‐poly(ethylene‐ ran ‐butylene)‐ block ‐polystyrene (SSEBS). As the potential of the ITO electrode was cycled from +0.7 to +1.3 V, the analyte changed from the colored [Ru(bpy) 3 ] 2+ complex to colorless [Ru(bpy) 3 ] 3+ complex and the change in absorbance at 450 nm was used as the optical signal for quantification. Calibration curves were obtained for [Ru(bpy) 3 ] 2+ in natural well water, river water and treated tap water with detection limits of 108, 139 and 264 nM, respectively. A standard addition method was developed to determine an ‘unknown’ spike addition concentration of [Ru(bpy) 3 ] 2+ in well water. The spectroelectrochemical sensor determined the concentration of [Ru(bpy) 3 ] 2+ spiked into a sample of Hanford well water to be 0.39±0.03 µM versus the actual concentration of 0.40 µM.