Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

Lead can be determined conveniently by the classical or reversed FIA technique using photometric detection with 4-(2-pyridylazo)resorcinol ( c_PAR = 0.1 mol l^-1) in 0.1M borate buffer (λ 518 nm). For injected volumes of 50 μl, the lead concentrations can lie in the regions of 1-20 and 0.4=18 μmol l^-1, respectively. The selectivity of determination can be increased one to two orders of magnitude by masking with a mixture of EDTA ( 5 μmol l^-1), tartaric acid (20 μmol 1^-1) and KCN (2 mmol 1^-1). When combining the analysis with preconcentration on a 3 x 30 mm microcolumn of Spheron Oxin 1 000 chelating sorbent from 0.01M ammonium acetate solutions at pH 6.5 followed by elution with 0.1M-HCl, lead can be determined in concentrations of 0.1–1.2, 0.02–0.85 or 0.01–0.60 μmol 1^-1 for sample volumes of 5, 10 or 20 ml, respectively. The repeatability of determination for ten independent measurements on 5, 10 and 20 ml sample volumes at c_Pb = 0.2, 0.05 μmol 1^-1, respectively, was better than 4.7, 2.8 and 6.2%, respectively. The method_i of preconcentration on a chelating sorbent was applied to the analysis of clean industrial wastewaters. The relative deviation of the lead concentration did not exceed 6.5% in comparison with data obtained by AAS.