The HPLC chromatograms of standard ( a ) and samples. ( b ) LJF sample; ( c ) LF sample; S: secologanic acid. Column: An Agilent <t>ZORBAX</t> <t>XDB</t> <t>C18</t> (4.6 × 250 mm, 5 μm) column; column temperature, 30 °C; mobile phases: 0.1% phosphoric acid solution (A) and acetonitrile (B), using a gradient elution of 5–15% B at 0–20 min, 15–23% B at 20–25 min, 23–95% B at 25–26 min, and 95% B at 26–30 min; flow rate: 1.0 mL/min; detection wavelength: 240 nm; injection volume: 10 µL.
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