Membrane Filtration of Lead, Cobalt, and Nickel in Water and Fertilizer Samples for Enrichment/Separation and Flame Atomic Absorption Spectrometric Determination

A membrane filtration procedure based on the adsorption of 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol (5-Br-PADAP) chelates of Pb(II), Co(II), and Ni(II) on a cellulose acetate membrane filter has been investigated. Determination of the analyte elements was performed by flame atomic absorption spectrometry. The effects of some parameters including pH, amount of 5-Br-PADAP, etc., on the recovery of the analyte elements were investigated, including influences of some matrix ions. The preconcentration factor found was 15. The detection limits for lead, cobalt, and nickel were 15.6 mu g L-1, 8.9 mu g L-1, and 19.5 mu g L-1, respectively. The validation of the procedure was verified using the addition-recovery test for real samples and analyzing a certified reference material. The procedure was successfully applied to the determination of analyte ions in environmental samples, including natural water samples.