Influence of triton X-100 in a micellar solution and in an emulsion on the polarographic behaviour of lead and the determination of lead in paint driers and varnishes by differential-pulse polarography

Abstract

The polarographic behaviour of Pb(II) in an aqueous medium, in aqueous Triton X-100 (2%m/V) and in a toluene-water emulsion was studied in 0.1 M potassium nitrate-0.15 M nitric acid. The Triton X-100 decreases the Pb(II) peak height in aqueous solution and emulsified media by 58 and 37%, respectively. Both media shift the Pb(II) peak potential from –420 mV to more cathodic values, –550 and –600 mV, respectively. The polarographic process of Pb(II) is controlled by diffusion in the above three media. The process is reversible in an aqueous medium and the addition of Triton X-100 makes the process irreversible; the emulsion improves the reversability of the polarographic process. A satisfactory method has been developed for determining lead in driers and varnishes by means of emulsion formation, using emulsified aqueous standards. The emulsion formation technique was used in a polarographic study of the nitrotoluene produced during the release of lead from driers and varnishes with concentrated nitric acid.