Ultrasound-Assisted Emulsification–Microextraction Combined with Flame Atomic Absorption Spectrometry for Determination of Trace lead in Water Samples

Abstract

The process of ultrasound-assisted emulsification–microextraction (USAEME) was successfully applied for the extraction and preconcentration of trace lead from water samples, prior to flame atomic absorption spectrometry (FAAS). In the proposed approach, dithizone was used as a chelating agent; carbon tetrachloride was selected as extraction solvent. Some effective parameters on the microextraction and the complex formation were selected and optimized. These parameters included extraction solvent type as well as extraction volume, time, temperature, and pH, the amount of the chelating agent, and salt effects. Under optimum conditions, an enrichment factor of 91 was obtained from only 7.0 mL of water sample. The calibration graph was linear in the range of 3.76-600 µg/L with a detection limit of 1.14 µg/L. The relative standard deviation (R.S.D) for ten replicate measurements of 20 and 600 µg/L of lead were 3.23 and 2.56%. This proposed method was successfully applied to tap water, river water and sea water, and accuracy was assessed through the analysis of certified reference water or recovery experiments. Operation simplicity, low cost, high enrichment factor, and low consumption of the extraction solvent are the main advantages of the proposed method.