resumo
The electronic tongue (ET) multisensor system has been employed for the detection of metal-oxygen cluster anions (polyoxometalates) containing vanadium (IV/V) atoms. Sensitivity of a variety of potentiometric chemical sensors with plasticized polyvinyl chloride and chalcogenide glass membranes was evaluated with respect to vanadyl/vanadate ions, decavanadate and a series of Keggin-type polyoxometalates (POM) such as alpha-[(SiW11VO40)-O-IV](6-), alpha-[(SiW11VO40)-O-V](5-), alpha-[(BW11VO40)-O-IV](7-), alpha-[(BW11VO40)-O-V](6-), alpha-[(PW11VO40)-O-IV](5-) and alpha-[(PW12-nVnO40)-O-V]((3+n)-) (n = 1, 2, 3). Sensor's responses to vanadium complexes were evaluated in the pH range of 2.4-6.5 and a set of sensors appropriate for detecting a variety of vanadium species was selected. Such sensor array was able to distinguish different vanadium complexes allowing their simultaneous quantification in binary (V(IV)/V(V)) Mixtures. The vanillyl alcohol oxidation with alpha-[(SiW11VO40)-O-V](5-) was monitored using ET to evaluate the capacity of proposed analytic system to detect simultaneously V(IV)/V(V) in POM under dynamic equilibrium. ET was demonstrated to be a promising tool for the discrimination and quantification of vanadium-containing POMs at different oxidation states. In particular, such a system could represent a significant interest for the mechanistic studies of redox reactions with POMs. (c) 2006 Elsevier B.V. All rights reserved.
palavras-chave
TWO-DIMENSIONAL W-183; CHEMICAL SENSORS; NMR CHARACTERIZATION; ELECTRONIC TONGUE; DELIGNIFICATION; SPECIATION; MECHANISM; VALENCE; ANIONS
categoria
Chemistry
autores
Rudnitskaya, A; Evtuguin, DV; Gamelas, JAF; Legin, A
nossos autores
Dmitry Evtyugin
Professor Associado com Agregação