title: Trace level enrichment of lead from environmental water samples utilizing dispersive liquid-liquid microextraction and quantitative determination by graphite furnace atomic absorption spectrometry.
abstract: Dispersive liquid-liquid microextraction (DLLME) was developed and successfully applied, as a sample preconcentration and extraction method, for the determination of trace quantities of lead (Pb) in environmental water samples utilizing graphite furnace atomic absorption spectrometer (GFAAS). Experimental parameters optimized include; extraction and disperser solvent types and their volumes, pH, extraction period, effect of the co-existing ions and the amount of chelating agent, ammonium pyrrolidine dithiocarbamate (APDC). Under the optimized conditions, enrichment factor of 195 at 5 μg L(-1) level and detection limit of 0.16 μg L(-1) were obtained. Linearity from 25-75 μg L(-1) with R(2) of 0.995 was achieved. The procedure was validated utilizing four environmental water samples at the spiking levels of 10 and 20 μg L(-1) and the corresponding recoveries ranged from 89.6 to 95.1% and 91.6 to 97.1%, respectively, indicating the reliability and applicability of the method for selective extraction of trace level lead.
authors.affiliation: a Department of Chemistry , Addis Ababa University , Addis Ababa , Ethiopia.
authors.forename: Endale
authors.initials: E
authors.lastname: Teju
authors.forename: Bezuayehu
authors.initials: B
authors.lastname: Tadesse
authors.forename: Negussie
authors.initials: N
authors.lastname: Megersa
mesh_terms: D002614:Chelating Agents; D005002:Ethiopia; D005618:Fresh Water / Q000737:chemistry*; D006108:Graphite; D007854:Lead / Q000032:analysis / Q000302:isolation & purification*; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods*; D011759:Pyrrolidines; D015203:Reproducibility of Results; D013054:Spectrophotometry, Atomic / Q000379:methods; D013859:Thiocarbamates; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D002614:Chelating Agents; D011759:Pyrrolidines; D013859:Thiocarbamates; D014874:Water Pollutants, Chemical; C020972:pyrrolidine dithiocarbamic acid; D007854:Lead; D006108:Graphite