Fx 10 lc pumps

The LC system consisted of a Flexar LC Perkin-Elmer (Waltham, MA, USA) with two Flexar FX-10 LC pumps, a Flexar solvent manager, a 275-Flexar autosampler, and a Flexar LC PE200 column oven. LC analyses were performed on a 100 mm × 2.1 mm i.d. 3 μm, LUNA 3U C18 column (Phenomenex, Torrance, CA, USA) and the column temperature was set at 25 °C. A volume of 10 μL of sample was injected using an injection loop of 15 μL in partial loop mode. The mobile phase consisted of MilliQ water (solvent A) and ACN (solvent B). The flow rate was set at 500 μL/min. The column was equilibrated (A:B; v/v) in 90:10 (5 min), and elution was carried out with the following steps; 90:10 (5 min), 80:20 (5 min), 70:30 (5 min), 60:40 (5 min), 50:50 (5 min), a linear gradient increasing from 50% B to 100% (5 min), and 100% B (7 min).