Fig. 3.

The production and composition of chito-oligosacharide. The analyses were performed using ultra-high performance liquid chromatography with Thermo Scientific Orbitrap mass spectrometry systems (UHPLC–Orbitrap MS). And all mass spectra were acquired in the positive ion mode, within the mass range 100–2000 m/z. Separation was achieved using Welch ultimate XB-NH2 (100 × 2.1 mm, 3 μm). The injection volume used was 5 μl. The mobile phase was composed of A (acetonitrile) and solvent B (0.3% aqueous ammonia, V/V) with a linear gradient elution: 0–2 min, 75–40% A; 2–5 min, 40–40% A; 5–8 min, 40–75% A, and held for 2 min, at a flow rate of 400 μl/min, resulting chromatographic full-width-at-half-maximum (FWHM) of 3–5 s. Analytical data were collected at resolution from 30,000 and scanning rate 1–12 scans/s.