Resolution of strongly overlapped responses in square-wave voltammetry by using the Kalman filter

Various approaches have been proposed for resolving overlapped voltammograms. Such methods have become incresingly important since the advent of small computers and commercial electrochemical instrumentation capable of rapid-scan techniques. The combination of high-resolution, rapid-scan square-wave voltammetry and a linear, recursive estimator known as the Kalman filter is described. Results of the application of this combination to mixtures of thallium(I) and lead(II) in 0.9 M nitric acid are shown. Practical considerations for filter usage such as the choice of models, variances, and initial guesses are discussed, as are limits to the filter. With the Kalman filter, it was possible to quantify thallium in solutions containing as much as a 30-fold excess amount of lead, and it was possible to quantify lead in solutions containing a 60-fold excess amount of thallium. The filter is thus a useful tool for use with empirical models in multicomponent quantitation.