Phenolic Compounds Quantification by HPLC

The phenolic compounds confirmation analysis by HPLC (1260 Infinity ll, Agilent Technologies, Santa Clara, CA, USA) was accomplished by Agilent ZORBAX Eclipse Plus C18 column (250 × 4.6 mm, 5 μm). The phenolic compounds were separated under gradient conditions with a flow rate of 0.8 mL/min. Column temperature was 35 °C and volume injection was 10 µL. The wavelength was 280 nm. The solvents used in the elution process were an aqueous solution of 100% methanol (phase A) and 0.02% (v/v) formic acid (phase B). The samples were eluted according to the linear gradient, the phase-time program was as follows: 0–10% A (0–5 min), 10–20% A (5–10 min), 10–35% A (10–20 min), 35–40% (20–35 min), 40–75% A (35–40 min), 75–10% A (40–45 min). The peak areas of the samples were compared with those of the internal standards and quantified [26 (link)].