UPLC Analysis of Polyphenol Composition

Polyphenol composition was obtained through ultra-high-performance liquid chromatography (UPLC) using an ACQUITY Ultra Performance system linked to a PDA 2996 photodiode array detector (Waters, Milford, MA, USA), linked to an Empower software (Waters). The analysis was performed following the method of Ombra et al. [17 (link)] at λ = 280 nm with a reversed-phase column (BEH C₁₈, 1.7 µm, 2.1 mm× 100 mm, Waters), at 30 °C, at a flow rate of 250 μL/min, and with pressure ranging from 6000 to 8000 psi. The effluent was introduced to an LC detector (scanning range 210–400 nm, resolution 1.2 nm). The injection volume was 5 μL. Phenolic compounds were identified and quantified through comparison of the peak areas on the chromatograms of samples with those of diluted standard solutions.