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Spectroelectrochemical Sensing Based on Multimode Selectivity Simultaneously Achievable in a Single Device.
Author(s) -
Maizels Mila,
Seliskar Carl J.,
Heineman William R.,
Bryan Samuel A.
Publication year - 2002
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/1521-4109(200211)14:19/20<1345::aid-elan1345>3.0.co;2-e
Subject(s) - ferrocyanide , ionic strength , absorbance , indium , indium tin oxide , electrochemistry , materials science , chemistry , ion exchange , potassium ferrocyanide , inorganic chemistry , electrode , analytical chemistry (journal) , chemical engineering , ion , thin film , chromatography , nanotechnology , optoelectronics , organic chemistry , aqueous solution , engineering
A ferrocyanide spectroelectrochemical sensor has been evaluated on Hanford tank waste simulant solution. The sensor consists of an indium tin oxide optically transparent electrode coated with a thin film of porous silica containing immobilized PDMDAAC as an anion exchanger. Ferrocyanide is quantified by the absorbance change at 420 nm that accompanies electrochemical modulation of ferrocyanide that partitions into the film. Hanford tank waste simulant mimics the contents of tanks in which radioactive waste is stored. A solution of the simulant is a complex mixture of high pH (10) and high ionic strength that contains ferrocyanide. Systematic evaluation of the species in the simulant solution showed the only significant interference to be competition by the anions in the simulant with the preconcentration of ferrocyanide into the sensing film. Deterioration of the sensing film by the high ionic strength and alkaline conditions restricted its useful lifetime to about 40 min. Analysis of simulant with a sensor calibrated at high ionic strength gave 8.0 mM ferrocyanide compared to 8.2 mM obtained by FTIR.