Determination of lead in waters of Parana River by solid phase spectrophotometry

This paper presents the procedure for determination of lead in water samples by solid phase spectrophotometry. The procedure is based on reaction of Pb(II) ion with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol immobilized on an anion-exchange resin. Absorbance of the resulting coloured complex was measured directly at the solid phase. Detection limit of the method and sample throughput were 0.8 mu g L-1 and 2 h(-1), respectively. Relative standard deviation was 1.7% for 10.0 mu g L-1 Pb(II) concentration. The obtained calibration plot was linear within the analyte's concentration range starting from detection limit up to at least 100 mu g L-1, with a correlation coefficient of 0.9995. The proposed method was successfully applied to the determination of Pb(II) in natural water samples from Parana River in Argentina.