SIGNALS RATIO METHOD FOR RESOLUTION ENHANCEMENT IN DIFFERENTIAL-PULSEPOLAROGRAPHY AND RELATED TECHNIQUES

An efficient and simple resolution method based on signals ratio in ti me domain is proposed for differential pulse (DP) polarographic and re lated techniques. The ratio pseudo-DP polarograms are obtained dividin g the multianalyte DP polarogram with individual DP polarograms of a s ingle analyte. Using the same procedure for DP polarograms recorded fo r calibration diagrams and for DP polarograms of unknown binary mixtur es, well resolved ratio pseudo-DP polarograms are obtained. The method is applied to the model binary system of lead and thallium, having ap proximately 70 mV of DP polarographic peaks separation depending of th e medium used. DP polarograms of these two metal ions show significant overlapping which depends on their concentration ratio. The method pr oposed is able to resolve lead from at least 40-fold excess of thalliu m, and thallium from at least 20-fold excess of lead at micromolar con centration range with reproducibility better than 5%.