C18 ods guard column

The targeted phenolic compounds present in seaweeds were quantified by Agilent 1200 series HPLC (Agilent Technologies, CA, USA) equipped with a photodiode array (PDA) detector according to our previously published protocol of Gu et al. [112 (link)] and Suleria, Barrow, and Dunshea [63 (link)]. The sample’s phenolic compounds were extracted by conventional and ultrasonication. Sample extracts were filtered by the 0.45 μm syringe filter (PVDF, Millipore, MA, USA). A Synergi Hydro-RP (250 × 4.6 mm i.d.) reversed-phase column with a particle size of 4 µm (Phenomenex, Lane Cove, NSW, Australia) was protected by a Phenomenex 4.0 × 2.0 mm i.d., C18 ODS guard column. The injection volume of the sample or standard was 25 μL. The mobile phase A and B were of water/acetic acid (98:2, v/v) and acetonitrile/water/acetic acid (50:50:2, v/v/v), respectively. The gradient profile was 90–10% B (0–20 min), 75–30% B (20–30 min), 65–35% B (30–40 min), 45–55% B (40–60 min), 90–10% B (60–61 min), 90–10% B (61–66 min). The flow rate was 0.8, and the column was operated at room temperature. The wavelengths of 280, 320, and 370 nm were simultaneously selected at the PDA detector. Empower Software (2010) was used for instrument control, data collection, and chromatographic processing.

The targeted phenolic compounds in green banana flour were quantified using Agilent 1200 series HPLC (Agilent Technologies, Santa Clara, CA, USA) coupled with a photodiode array (PDA) reader by the previous published protocol of Suleria et al. with a few adjustments. A 0.45 µm syringe filter (PVDF, Millipore, MA, USA) was utilized to filter sample extracts. A Synergi Hydro-RP column (250 4.6 mm i.d.) with a 4 µm particle size (Phenomenex, Lane Cove, NSW, Australia) was guarded by a Phenomenex C18 ODS guard column (4.0 × 2.0 mm i.d.). The volume of injection of samples or standards was 20 µL. The mobile phases A and B were composed of water/acetic acid (98:2, v/v) and acetonitrile/water/acetic acid (55:43:2, v/v/v). The range of gradient profile was 10–25% B (0–20 min), 25–35% B (20–30 min), 35–40% B (30–40 min), 40–55% B (40–70 min), 55–80% B (70–75 min), 80–90% B (75–77 min), 90–100% B (77–79 min), 100–10% B (79–82 min), isocratic 10% B (82–85 min). The flow rate was 0.8 mL/min, and the column temperature was ambient. At the PDA detector, the wavelengths 280, 320, and 370 nm were chosen at the same time. The (2010) version of Empower 3 Software was utilized for device management, gathering data, and chromatography analysis.