Assessing a Spectroelectrochemical Sensor’s Performance for Detecting [Ru(bpy)3]2+ in Natural and Treated Water |
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| Authors: | Eme A. Abu Samuel A. Bryan Carl J. Seliskar William R. Heineman |
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| Affiliation: | 1. Department of Chemistry, University of Cincinnati, 301 Clifton Court, Cincinnati, OH 45221‐0172, USA;2. Pacific Northwest National Laboratory, Richland, WA 99352, USA |
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| Abstract: | 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. |
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| Keywords: | Spectroelectrochemical sensors SSEBS ITO electrode |
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