Determination of Ti(IV) at low levels by voltammetry

Accurate and rapid determination of Ti(IV) at low or trace levels in HClO4, HClO4–NaClO3, H2SO4, H2C2O4, H2C2O4–NaClO3 and H3PO4 media can be done by voltammetry at the mercury drop electrode. New reliable procedures implementing square wave and differential pulse voltammetries are described. Kinetic peak currents resulting from slow complex formation are proportional to the analytical concentration of Ti(IV). Calibration lines, figures of merit and formulae for the calculation of concentrations are given. Limits of quantification are determined with an accuracy of about ±10% using standard solutions. In acid oxalate–chlorate medium, where a catalytic reduction of Ti(IV) occurs, the precision and sensitivity of differential pulse voltammetry compare very favourably with other modern microanalytical methods. The limit of quantification is 10−7 M. In the other media, this limit lies between 10−5 and 10−6 M. remely simple mathematical formula for the contribution of the sphericity of the mercury drop on the peak current in square wave voltammetry in the case of slow charge-transfer reactions is incidentally given.