Poly(catechol) film modified glassy carbon electrode for ultratrace determination of cerium(III) by differential pulse anodic stripping voltammetry

Oxidative electropolymerization of resorcinol, catechol and pyrogallol at t he glassy carbon electrode in different media such as 0.10 M NaOH, 0.10 M p hosphate buffer (pH 7.00) or 0.10 M NaClO4 all gave water-insoluble films, adherent on the electrode surface. Amongst them electropolymerization of ca techol at the GC electrode in 0.10 M NaOH provided a highly sensitive and s elective film for Ce(III) and therefore, this poly(catechol) film modified glassy carbon electrode was exploited for the selective preconcentration of Ce(III) at open circuit, followed by its determination by differential pul se anodic stripping voltammetry both in batch and flow systems. Factors aff ecting the accumulation, stripping and removal steps were investigated and an optimized procedure was then developed. Under optimized conditions, for batch determination, the calibration plot was linear in the concentration r anges 2.00 x 10(-9) M-1.00 x 10(-8) M and 2.00 x 10(-8) M-1.00 x 10(-7) M C e(III). A detection limit of 2.0 x 10(-10) M (0.027 ppb) (SN = 3) was found for a 10 min accumulation. For six successive determinations of Ce(III) at concentrations of 2.00 x 10(-7), 2.00 x 10(-8) and 2.00 x 10(-9) M, relati ve standard deviations were 3.36%, 1.76% and 4.08%, respectively. Similar r esults were obtained for continuous flow analysis. Interference from select ed foreign ions and substances were examined. The developed method was appl ied to Ce(III) determination in human urine, both in batch and continuous f low systems.