Extraction and determination of heavy metals in soil and vegetables irrigated with treated municipal wastewater using new mode of dispersive liquid�liquid microextraction based on the solidified deep eutectic solvent followed by GFAAS

Abstract

BACKGROUND: In this research, a new extraction method based on dispersive liquid�liquid microextraction and the solidification of deep eutectic solvent has been developed for the determination of heavy metals in soil and vegetables prior to their analysis by graphite furnace atomic absorption spectrometry (GFAAS). In this method, a green solvent consisting of 1-decyl-3-methylimidazolium chloride and 1-undecanol was used as an extraction solvent, yielding the advantages of material stability, low density and a suitable freezing point near room temperature. RESULTS: Under optimal conditions, enrichment factors are in the range of 114�172. The calibration graphs are linear in the range of 0.02�200 µg kg�1 and limits of detection are in the range of 0.01�0.03 µg kg�1. Repeatability and reproducibility of the method based on seven replicate measurements of 0.80 µg kg�1 of Hg and 0.20 µg kg�1 of Pb and Cd in analyzed samples were in the range of 2.3�4.1 and 3.7�6.6, respectively. CONCLUSION: A new deep eutectic solvent consists of two parts: 1-decyl-3-methylimidazolium chloride and 1-undecanol in a molar ratio of 1:2. The accuracy of the proposed procedure was also assessed by determining the concentration of the studied metal ions in a polluted farmland soil standard reference material. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industr