Determination of nanogram amounts of cadmium in water by electrothermal atomic absorption spectrometry after flotation separation

A method is described for the flotation an determination of ng-levels of cadmium in water. Cadmium in a 1-l sample of water is coprecipitated with hydrated zirconium oxide at pH 9.1 ± 0.1. The precipitate is floated with the aid of a surfactant solution and small air bubbles, separated and dissolved in dilute hydrochloric acid. The cadmium content is determined by electrothermal atomic absorption spectrophotometry. The method is applied to the determination of ng l^?1 levels of cadmium in fresh water. The time required for preconcentration of cadmium from a 1-l sample is 20 min per sample, after 20 min stirring.