Determination of Lead in Aqueous Samples using a Flow Injection Analysis System with On-line Preconcentration and Spectrophotometric Detection

Abstract

A simple and accurate flow injection analysis systems coupled withspectrophotometric detetection was developed to preconcentration and determination of leadin aqueous samples. The FIA systems based on the reaction of lead (II) with 4-(2-pyridylazo)resorcinol (PAR) in buffer pH 9 with an adsorption maximum at 523 nm. The developedflow system includes a lead preconcentration step in a column packed with Amberlite XAD-7 resin. The optimum preconcentration system, chemical and FIA variables wereinvestigated. The proposed method has a linear calibration range 0.05-0.90 mg L-1 of leadwith the regression y = 1.522x???0.031, R2 = 0.9963, whereas the observed detection limit (3S,n = 20) was 11 ??g L-1 and the percentage of recovery of 102%. The proposed system showgood precision and accuracy with relative standard deviations is 2.4%. The samplingfrequency was 12 determinations per hour. The method has been applied to the determinationof lead in real water samples with a preconcentration factor of 3.