Stripping voltammetric determination of zirconium with complexing preconcentration of zirconium(IV) at a morin-modified carbon paste electrode

A sensitive, selective and economic stripping voltammetry is described for the determination of trace amounts of zirconium at a morin-modified carbon paste electrode (morin-MCPE). Zirconium(IV) can be preconcentrated on the surface of the morin-MCPE due to forming the Zr(IV)-morin complex. The complex produces two second-order derivative anodic peaks at 0.69 V (vs. SCE) and 0.75 V when linear-scanning from 0.0 to 1.0 V. The optimum analytical conditions are: 2.2 mol L-1 HCl, 0.0 V accummulation potential, 90 s accummulation time, 250 mV s(-1) scan rate. A linear relationships between the peak currents at 0.75 V and the Zr(IV) concentration are in the range of 2.0 x 10(-s) to 3.0 x 10(-6) mol L-1. The detection limit is 1.0 x 10(-8) mol L-1 (S/N = 3) for 120 s accumulation. The RSD for determination of 4.0 X 10(-7) mol L-1 Zr(IV) is 4.8% (n = 8). The proposed method has been applied to determine zirconium in ore samples, unnecessarily extracted.