[Determination of lead (II) in food using the ICP-AES method after condensation on the lanthanum carrier].

The purpose of the study was utilization of emission atomic absorption spectrometry with excitation in induction-coupled plasma, and molecular spectrometry for determination of lead in milk and dairy products after condensation in ammonia atmosphere. Two methods were proposed for lead condensation on lanthanum carrier--in form of hydroxide or sulphide. By coprecipitation of lead on lanthanum in ammonia atmosphere lead separated and selectively condensed. Other metals (Zn, Cd, Cu) coexistent in food products remained as amino complexes in the solution. The sediment remaining after lead condensation was dissolved in 2 mol/dm3 hydrochloric acid solution. The selected conditions of lead separation and condensation make possible determination of the metal in the concentrations from 0.01 mcg/ml to 0.2 mcg/ml by the ICP-ARS and dithizone methods. The method of condensation and determination was used for lead determination in milk and dairy products in concentrations below 1.5 x 10(-5)%. The studied food products were mineralized with concentrated HNO3, H2SO4 and perhydrol. This mineralization method makes it possible to determine in one mineralisate directly copper and zinc by ICP-ARS and dithizone methods, and lead after condensation. The obtained results were precise and reproducible.