Determination of Trace Amounts of Lead and Manganese in Water Samples After Simultaneous Preconcentration onto Modified Amberlite XAD-4 Resin

Abstract

A procedure for simultaneous separation and preconcentration of trace amounts of manganese and lead has been proposed. It is based on the adsorption of manganese and lead ions onto a column of Amberlite XAD-4 resin loaded with pyrocatechol reagent. Manganese and lead were quantitatively retained on the column in the pH range 4.0-6.5 at a flow rate of 2 mL/min. The manganese and lead ions were eluted with 5.0 mL of 4 M HNO3 solutions. Manganese and lead were measured by flame atomic absorption spectrometry. In this case, 100.0 ng manganese and 1000.0 ng lead were concentrated in the column from 800 mL of aqueous sample, where their concentrations were as low as 0.125 and 1.25 ng/mL, respectively. Seven replicate determinations of mixtures of 1.0 microg/mL manganese and 2.0 microg/mL lead in the final solution gave a mean absorbance of 0.1926 and 0.0832 with RSD values of +/- 1.1 and +/- 1.2%, respectively. The LODs were 1.76 ng/mL for Mn(ll) and 37.28 ng/mL for Pb(ll) (3 delta(bl)/m) in the final solution, with a preconcentration factor of 160. Sensitivities for 1% absorbance for Mn(ll) and Pb(ll) were 7.0 and 74.7 ng/mL, respectively. The interference of a large number of anions and cations has been studied and the optimized conditions were used for determination of trace amounts of manganese and lead in various environmental and standard samples.