were used.
The following solvents constituted the mobile phase: A. 4.5% formic
acid and B. acetonitrile. The following elution conditions were
applied: 0–1 min, 5% B isocratic; 1–6 min, linear gradient from
5–10% B; 6–26 min, linear gradient 10–20% B; 26–33 min, linear