Ultrasonic Assisted Liquid Phase Microextraction of Pb2+ Based on Deep Eutectic Solvent Followed by Electrothermal Atomic Absorption Spectrometry

This study presents an efficient, rapid, green, and low-cost method for preconcentrating trace levels of Pb2+ using ultrasonic-assisted liquid-phase microextraction (UA-LPME) followed by electrothermal atomic absorption spectrometry. We used sulfanilamide as a complexing agent to form a hydrophobic complex with Pb2+, and a mixture of choline chloride-phenol as an extraction solvent. We investigated and optimized several parameters affecting the analyte's extraction recovery, including pH of the sample solution, concentration of the complexing agent, mole ratio of choline chloride phenol, volume of extraction solvent, volume of tetrahydrophoran (as an aprotic solvent), and ultrasonic time. Under the optimized conditions, we found that the proposed method has a linear range of 0.5-10 µg L-1 Pb2+ and a limit of detection of 0.16 µg L-1 Pb2+ (n=6). The proposed method's accuracy was verified using certified reference material-trace metals in drinking water (CRM-TMDW) samples. We also successfully used the proposed method to determine trace levels of Pb2+ in different water samples. In conclusion, our study offers an effective UA-LPMEbased method for preconcentrating trace levels of Pb2+ that can be applied to environmental monitoring and analysis.