Ascentis express es c18 column

α-DC analysis was conducted using an Ultrahigh Performance Liquid Chromatography apparatus (Shimadzu, Columbia, MD) consisting of two pumps LC-30AD, an SPD-M20A photo diode array detector (PDA), DGU–20A5 degasser, SIL–30AC autosampler (operated at 4°C) and CTO-20 AC column oven. The UHPLC system was controlled by a personal computer equipped with LabSolutions software operating in a Windows XP. The separation was achieved following the method described by Papetti et al. [18 (link)] using Ascentis Express ES-C18 column (150 × 4.6 mm, 2.7 μm particles; Sigma-Aldrich, St. Louis, MO) with a UHPLC pre-column filter (UltraShield Analytical Scientific Instruments, Richmond, CA) operating at 25.0 ± 0.5°C. The analytes were eluted with a flow rate of 0.3 mL/min using 0.1% formic acid in water (A) and methanol (B) as eluents. The 120 min gradient is described as follows: 0–5 min (90–85% A), 5–13 min (85–80% A), 13–40 min (80% A), 40–65 min (80–70% A), 65–90 min (70–50% A), 90–100 min (50–0% A), 100–105 min (0% A), and 105–110 min (0–90% A); the column was then re-equilibrated with the initial mobile phase for 10 min. The injection volume was 5 μL. The PDA detector was set at 314 and 335 nm to record the peaks, and UV spectra recorded from 215 to 420 nm. Before injection sample solutions were filtered with PVDF syringe filter (13 mm, 0.22 μm; Millipore Millex, Billerica, MA, USA).