Signals Ratio Method for Resolution Enhancement in Differential Pulse Polarography and Related Techniques

An efficient and simple resolution method based on signals ratio in time domain is proposed for differential pulse (DP) polarographic and related techniques. The ratio pseudo-DP polarograms are obtained dividing the multianalyte DP polarogram with individual DP polarograms of a single analyte. Using the same procedure for DP polarograms recorded for calibration diagrams and for DP polarograms of unknown binary mixtures, well resolved ratio pseudo-DP polarograms are obtained. The method is applied to the model binary system of lead and thallium, having approximately 70 mV of DP polarographic peaks separation depending of the medium used. DP polarograms of these two metal ions show significant overlapping which depends on their concentration ratio. The method proposed is able to resolve lead from at least 40-fold excess of thallium, and thallium from at least 20-fold excess of lead at micromolar concentration range with reproducibility better than 5%.