UPLC was performed using a Waters Acquity systemequipped with binary solvent delivery pump and an autosampler. The chromatographic separation was performedon Waters Acquity UPLCs BEH C18 column (2.1 50 mm,1.7 mm) at a column temperature of 251C. The mobile phaseconsisted of (A) 0.2% aqueous formic acid and (B)acetonitrile with a flow-rate of 0.4 mL/min using a gradientelution of 30% B at 0–2.5 min, 30–35% B at 2.5–3.0 min,35% B at 2.5–8.6 min, 35–45% B at 8.6–9.6 min, 45–100% Bat 9.6–13.0 min.