Solid-phase extraction (SPE) using an immobilized crown ether as an extractant was applied to the flow injection FAAS determination of Pb" with in-valve minicolumn preconcentration and separation. Lead(I1) was first loaded on to a column filled with the crown ether resin from a nitric acid solution (0.8-2.0 mol dm-3). Among the eluents studied (oxalic acid, ammonium oxalate, citric acid, sodium citrate and tartaric acid), 0.05 mol dm-3 ammonium oxalate was found to be most suitable. Calibration was made either by variation of the preconcentration time (using a single standard) or by using standard solutions of different concentrations. The detection limit ( 3 ~) was found to be 0.08 pg of Pb and an RSD of 4.1% was achieved for 0.8 pg of Pb" ( n = 15). An upper limit for the working range of 5 pg of Pb" per sample was found. Interferences of cationic and anionic sample components were found to be negligible. Application to the determination of Pb" in digested soil samples is described and the method was validated by using certified reference materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.