Automated Microextraction Separation of Lead from Vegetable Oils for Determination by Atomic Absorption Spectrometry

Hydrophilic deep eutectic solvents based on choline chloride, carboxylic acids, and water are studied as “green” extractants for the liquid–liquid microextraction of lead from vegetable oils. An automated method is proposed for the microextraction of lead from vegetable oils into a ternary deep eutectic solvent based on choline chloride, lactic acid, and water. The carboxylic acid in the extractant ensured the effective mass transfer of lead due to complexation. Water in the extractant made it possible to reduce its viscosity to automate liquid–liquid microextraction. The analytical capabilities of the developed method are demonstrated on an example of determining lead in vegetable oils by atomic absorption spectrometry with electrothermal atomization. The limit of detection (3σ) for lead is 0.3 μg/kg. The developed method does not require sample mineralization.