*2.2. NADES Preparation*

The NADES was obtained according to a previous work, with slight modifications [17]. Lactic acid, glucose, and water (5:1:3 molar ratio) were mixed by means of a magnetic stirrer at 50 ◦C for about 90 min, until obtaining a clear solution. Further dilution of the

components in such molar ratio was carried out with 20% (*v*/*v*) water to reduce solvent viscosity. Previous studies reported the possibility of using water to tailor the solvent properties, mainly viscosity [18,19]. In particular, Pisano et al. proved that the same NADES used in this study held its supramolecular structure throughout dilutions [19].

#### *2.3. Extraction with NADES and Spectrophotometric Analysis of the Extract (NADES-UV Method)*

The EVOO sample (0.5 g) was submitted to extraction with 5 mL of NADES. After intense agitation with a vortex (5 min), centrifugation was performed for 10 min at 6000 rpm. The lower layer (NADES plus phenolics) was recovered, centrifuged again at 9000 rpm for 5 min and, after being recovered, finally filtered at 0.45 μm using nylon filters (VWR International, Center Valley, PA, USA).

The NADES extracts were analyzed by UV-Vis spectrophotometry in the wavelength range 250–400 nm by means of an Agilent Cary 60 spectrophotometer (Agilent Technologies, Santa Clara, CA, USA). The acquisition parameters were the following: 1 cm optical path, 2 nm slit, and 60 nm min−<sup>1</sup> scan rate. Pure NADES was used for baseline correction. For quantitation purposes, calibration curves of OHTyr and Tyr in NADES were built in the ranges 3–30 mg L−<sup>1</sup> and 5–40 mg L−1, and at wavelengths 299 nm and 290 nm, respectively. A total phenolic calibration curve was also built at 282 nm in the range of total 8–70 mg L−<sup>1</sup> by using mixtures of OHTyr and Tyr, and employing for each compound the same concentration range reported above.
