Preconcentration and Determination of Lead for Trace Levels in Water and Wastewater Samples by Vortex-Assisted Microextraction Using TPAS as a New Synthetic Complexing Agent with Electrothermal Atomic Absorption Spectroscopy Detection

A simple and rapid solidified vortex assisted 1-undecanol based liquid–liquid microextraction technique was proposed for preconcentration of trace levels of lead ions. The extraction solvent (1-undecanol) was dispersed into the aqueous samples by the assistance of vortex agitator. 100 μL of 1-undecanol containing ethyl (2Z)-3-[(5-chloro-7-methyl[1,3]thiazolo[5,4-d]pyrimidin-2-yl)amino]-2-cyano-3-(methylsulfanyl)prop-2-enoate (TPAS) as a new chelating agent (0.1%w/v) was transferred to the water samples containing lead ions. The hydrophobic complex was extracted into 1-undecanol and the sample vial was cooled in an ice bath for 5 min. The solidified extract was transferred into a conical vial where it was melted immediately, and 20 μL of this solution was injected and analyzed by Graphite Furnace Atomic Absorption Spectrometry (GFAAS). Several variables such as sample pH, concentration of TPAS, volume of 1-undecanol and extraction time were investigated in details and optimum conditions were obtained. Under the optimum conditions, the Limit Of Detection (LOD) was 0.02 μg L-1 for lead and Relative Standard Deviation (RSD %) for five replicate determinations of 1 μg/L of lead was 5.6%. The results for determination of lead in reference material, three samples of wastewater, well, tap, river and aqueduct water demonstrated the accuracy, recovery and applicability of the presented method.