Environmental Laboratory, NSTRI, Tehran, Iran
The dispersive liquidâ€“liquid microextraction (DLLME) method for determination of Pb+2 and Cd+2 ions in the environmental water samples was combined with inductively coupled plasma-atomic emission spectrometry (ICP-AES). Ammonium pyrrolidine dithiocarbamate (APDC), chloroform and ethanol were used as chelating agent, extraction solvent and disperser solvent, respectively. Some effective parameters on the microextraction and the complex formation were selected and optimized. These parameters included extraction and disperser solvent type as well as their volume, extraction time, salt effect, pH, sample volume and amount of the chelating agent.Â Â Under the optimum conditions, the enrichment factor of 75 and 105 for Cd+2 and Pb+2 ions respectively was obtained from only 5.00mL of water sample. The detection limit (S/N=3) was 12 and 0.8ngmLâˆ’1 for Pb and Cd respectively. The relative standard deviation (RSDs) for five replicate measurements of 0.50 mgLâˆ’1 of lead and cadmium was 6.5 and 4.4 % respectively. Mineral, tap, river, sea, dam and spiked water samples were analyzed for Cd and Pb amount.