Artículos de revistas
Electrochemical investigation of some aromatic redox mediators immobilised on titanium phosphate
Registro en:
Quimica Analitica. Elsevier Informacion Professional, S A, v. 19, n. 15, n. 27, 2000.
0212-0569
WOS:000165192000004
Autor
Kubota, LT
Munteanu, F
Roddick-Lanzilotta, A
McQuillan, AJ
Gorton, L
Institución
Resumen
Some phenazines, phenoxazines, and phenothiazines as well as riboflavin were immobilised on amorphous titanium phosphate (TP) by adsorption from aqueous solutions. The immobilised organic redox compounds revealed a reasonable electron transfer rate and with a formal potential (E degrees') at pH 7.0 more positive than that observed for their corresponding aqueous soluble counterparts. This shift in the E degrees' was partly assigned to the acidity of TP. The E degrees' of the immobilised redox compound remained virtually constant with a variation of the solution pH between 1 and 8 and was attributed to the protection effect of the matrix. Attenuated total reflectance infrared spectroscopy (ATRIS) of methylene blue and riboflavin adsorbed onto TP deposited on ZnSe-prism was also used to shed further light on the interaction between these aromatic redox compounds and TP, as ATRIS is sensitive to the mode of adsorption of molecules on surfaces. Four of the immobilised compounds (Nile blue, methylene blue, toluidine blue O, methylene violet) were shown to be efficient as electron transfer mediators to electrocatalytically oxidise NADH in aqueous solution at pH 7.0. The kinetic parameters such as apparent Michaelis-Menten constant were obtained for these four immobilised mediators. 19 1 15 27