Development and Validation of a Liquid-Liquid Microextraction Method Based on a Hydrophilic Deep Eutectic Solvent for effective extraction of tert-butylhydroquinone from edible oils, followed by HPLC-UV analysis

A green liquid-liquid microextraction (LLME) procedure based on hydrophilic deep eutectic solvents (DESs) and vortex-assisted agitation was developed to extract tert-butylhydroquinone (TBHQ) from edible oils. TBHQ is a synthetic phenolic antioxidant that is added to foods, such as edible oils, to prevent oxidation; however, this compound shows harmful effects on human health. The experimental conditions for LLME were optimized using experimental design tools. The variables considered in the optimization process were DES type, extracting phase volume (DES), water content, sample quantity (edible oil), stirring type, stirring time, centrifugation speed, and centrifugation time. The optimal conditions were 0.2 g of sample, 50 µL of DES composed of choline chloride (ChCl) and glycerol (1:2, molar ratio), vortex agitation for 10 min, and centrifugation at 5000 rpm for 8 min. The analysis was performed using High-Performance Liquid Chromatography-UV with UV detector (HPLC-UV), and the method was linear over 1–300 mg L ^− 1 (R ²  > 0.99), precise (RSDs < 5%), and accurate (recoveries from 97.99% to 100.49%), with detection and quantification limits of 0.040 and 0.134 mg L ^− 1 , respectively. Additionally, the method displayed no matrix effect and showed a satisfactory enrichment factor for TBHQ (2.03). The proposed method was successfully applied for the analysis of commercially available oil samples from different plant sources. Therefore, this method represents a new alternative method for monitoring TBHQ in edible oils.