Ultrasonic-assisted dispersive liquid-liquid microextraction based on hydrophilic deep eutectic solvents: Application to lead and cadmium monitoring in water and food samples

A green and innovative ultrasonic-assisted dispersive liquid-liquid microextraction using hydrophilic deep eutectic solvents (UA-HDES-DLLME) was developed for the selective and simultaneous extraction and enrichment of Pb (II) and Cd (II) in water and food samples for flame atomic absorption spectrometry. Several natural deep eutectic solvents (NADES) were used for the preparation of six different HDES and methyl violet was used as chelating reagent. Effective parameters such as pH, sonication time, methyl violet amount, DES type, dispersive solvent types, etc were optimized. Relative standard deviation (RSD) and preconcentration factor (PF) were 4.0% and 80. Low limits of detection (LOD, 1.3 ng mL^-1 for Pb (II) and 0.33 ng mL^-1 for Cd (II)) and quantification (LOQ, 4.0 ng mL^-1 for Pb (II) and 1.0 ng mL^-1 for Cd (II)) were found. The method accuracy was confirmed with analyses of certified reference materials.