A simple and quick approach for the determination of phthalic acid esters in beverage samples using temperature-assisted hydrophobic deep eutectic solvent-based dispersive liquid-liquid microextraction.

The quantification of phthalic acid esters (PAEs) in food and beverages is crucial for assessing human exposure levels. In this study, an environmentally benign microextraction methodology was developed utilizing a thymol-butyric acid deep eutectic solvent (DES) for the sensitive determination of six PAEs in beverage samples. Through systematic optimization, the temperature-assisted dispersive liquid-liquid microextraction (TA-DLLME) protocol achieved high enrichment factors (82.01-112.39) and extraction recoveries (66.94%-91.75%). Low detection limits (1.14-4.85 μg/L) were achieved, when coupled with HPLC-PDA analysis. The validated method was successfully applied to commercial beverages, with PAEs detected in 78.6% of samples at concentrations ranging from 4.04 to 47.1 μg/L. Mechanistic investigations through COSMO-RS and DFT calculations revealed that strong hydrogen-bonding interactions between the DES components and PAEs (ΔE = -17.29 to -26.28 kcal/mol) are the primary driver of the high extraction efficiency. With the advantages of low solvent consumption (≤200 μL) and rapid processing (<15 min), this approach provides a sustainable and practical alternative for routine monitoring of PAEs in liquid food products.