Trace level enrichment of lead from environmental water samples utilizing dispersive liquid-liquid microextraction and quantitative determination by graphite furnace atomic absorption spectrometry

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 mu g L-1 level and detection limit of 0.16 mu g L-1 were obtained. Linearity from 25-75 mu g 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 mu g 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.