ENHANCED SIGNAL-TO-BACKGROUND RATIOS IN VOLTAMMETRIC MEASUREMENTS MADE AT DIAMOND THIN-FILM ELECTROCHEMICAL INTERFACES

Large signal-to-background (S/B) ratios for the Fe(CN)(6)(3-/4-) and I rCl62-/3- redox couples in KCl have been observed in cyclic voltammetr ic measurements made at a conductive diamond thin-film electrode witho ut any conventional surface pretreatment. The S/B ratios were a factor of similar to 16 and 8 larger at diamond than at freshly polished gla ssy carbon (GC) for Fe(CN)(6)(3-/4-) and IrCl62-/3-, respectively. The polycrystalline diamond film, grown on a p-Si(100) substrate, possess ed significant cubic {100} faceting, as evidenced by AFM images, and w as of high quality, as indicated by Raman spectroscopy. The high, degr ee of electrochemical activity without surface pretreatment, the enhan ced S/B ratios, and the excellent response stability demonstrate that diamond might be an attractive new electrode material for electroanaly sis.