Cloud point preconcentration and flame atomic absorption spectrometry: application to the determination of manganese in milk and water samples

Cloud point extraction has been used for preconcentration of trace amount of manganese. The analyte was complexed with 1-(2-pyridylazo)-2-naphtol (PAN) and Triton X-114 was added as surfactant. After phase separation, based on the cloud point of the mixture, and dilution of the surfactant-rich phase with methanol, the enriched analyte was determined by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions, enhancement factor of 49.1 was obtained. The detection limit was 0.39 ng ml(-1)supercript stop for manganese. The proposed method was applied to the determination of manganese in milk and water samples.