2.4. Identification of Lipopeptides by LC-MS/MS

The extraction products were analyzed by ultra-performance liquid chromatography coupled with a high-resolution hybrid quadrupole Orbitrap mass spectrometer (Q Exactive, Thermo Fisher Scientific, Waltham, MA, USA). A C18 chromatographic column (ZORBAX Eclipse XDB, 2.1 × 150 mm, 3.5 μm; Agilent Technologies, Santa Clara, CA, USA) was used, and the mobile phases were as follows: solvent A, water with 0.1% formic acid; and solvent B, pure acetonitrile. The gradient program was as follows: 0–5 min, 5% B; 5–10 min, 5–30% B; 10–20 min, 30–50% B; 20–40 min, 50–80% B; 40–55 min, 80–95% B; and 55–60 min, 95–5% B. The flow rate was set at 0.3 mL min⁻¹. The ionization parameters were as follows: capillary temperature, 330 °C; electrospray voltage, 3.5 kv; tube lens voltage, 35 V; sheath gas flow rate, 40 L/min. Data were acquired in positive ion mode (mass scan range: m/z 900–1600). The analysis of the data was performed with Xcalibur software version 4.1 (Thermo Scientific, Waltham, MA, USA).