Determination of lead in paints by electro-oxidation in cationic surfactant—aqueous sodium hydroxide suspensions

It was shown that anodic voltammetry can be used to determine lead in paint samples by solubilizing the sample in an aqueous solution using a cationic surfactant (Hyamine 2389, prdominantly methyldodecylbenzyltrimethylammonium chloride). In addition to solubilizing the solid paint particles, the cationic surfactant increased the oxidation potential of water to the point where one could observe, in concentrated sodium hydroxide solutions, an anodic peak for the oxidation of lead monoxide to lead dioxide. If the surfactant was below the critical micelle concentration, the height of the peak was linearly proportional to the concentration of lead oxide in the paint. The technique was experimentally verified by comparing the concentration of lead in a commercial paint sample, as determined by x-ray fluorescence, with the concentration determined voltammetrically.