A green deep eutectic solvent-based aqueous two-phase system for the extraction of heterocyclic aromatic amines from marinating juice

In this work, an aqueous two-phase system (ATPS) based on a green deep eutectic solvent (DES) and inorganic salt is presented and applied for the simultaneous determination of heterocyclic aromatic amines (HAAs) in the marinating juice via ultra performance liquid chromatography (UPLC). First, six different betaine-based DESs were prepared, and betaine/1,4-butanediol (Bet/Buta) was chosen as the suitable extractant for the ATPS. Their structures were confirmed via Fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Subsequently, the factors influencing the ATPS were systematically investigated, and the optimal extraction parameters were obtained with a trichloroacetic acid concentration of 5% (w/v), 0.2 g of Bet/Buta, 0.6 g of an inorganic salt (K₂HPO₄), an extraction time of 1 min and a centrifugation time of 2 min. Under optimal extraction conditions, good linearities were obtained, with the correlation coefficient (R) ≥ 0.9995. The inter- and intraday precisions were 2.4–4.9% and 2.9–5.3%, respectively. The recoveries for the targeted HAAs ranged between 91.6 and 111.9%. The limits of detection (LODs) of 5.0–14.6 ng/g were obtained. In contrast to the frequently used solid-phase extraction (SPE) technique, the developed DES‒ATPS method, which has higher accuracy and better precision, has advantages of simplicity, speed, good environmental friendliness and low cost per sample. Finally, it was utilized to determine the four selected HAAs in actual samples of marinating juice to evaluate its applicability. Analytical GREEnness metric (AGREE), a novel greenness assessment tool, was tested to verify that this work was a relatively green analytical procedure. These findings demonstrate that the green and efficient DES−ATPS composed of the Bet/Buta DES and K₂HPO₄ shows great potential for extracting and enriching HAAs or other harmful substances from liquid food in pilot or large-scale operations.

Graphical abstract