Aquity ultra performance lc system

High-performance liquid chromatography (HPLC)/mass spectrometry (MS) analysis was conducted to estimate the major constituent of WEAOR. The analysis was performed on an AQUITY Ultra Performance LC system (Waters, San Jose, CA, USA) coupled with a Micromass Q-Tof Premier mass spectrometer (Waters). WEAOR was separated on an ACQUITY UPLC™ BEH C18 column (100 mm × 2.10 mm, 1.7 µm, Thermo Fisher Scientific, San Jose, CA, USA) by using a flow rate of 0.4 mL/min at 40 °C. The mobile phase of eluent A (aqueous formic acid solution, 0.1% v/v) and eluent B (acetonitrile with formic acid, 0.1%, v/v). The Micromass Q-Tof Premier MS and spray chamber conditions were capillary temperature, 350 °C; source voltage, 2.3 kV.

Reversed phase chromatography was performed using Waters AQUITY Ultra Performance LC system (Milford, MA, USA), with an analytical column BEH C18 1.7 µm, (2.1 × 100 mm, beds diameter: 1.7 µm). The column was heated to 40 °C and eluted with a gradient of solvents from 99% A and 1% B to 1% A and 99% B, where: A: water, with 0.1% formic acid; B: acetonitrile, with 0.1% formic acid.
The flow rate of the mobile phase was 0.4 mL/min. The sample volume was 5–10 µL. Samples were dissolved in 50% acetonitrile and were injected using AQUITY autosampler.
ESI-MS spectrometry was performed with SYNAPT G2-Si HDMS instrument (Waters Corporation, Milford, MA, USA) operating in positive ion mode. Acquisition of the data were performed at a range of 100–2000 m/z, using MassLynx software, version 4.1 SCN916 (Waters Corporation, Wilmslow, UK). Mass spectra were assigned with a multi-point external calibration using sodium iodide (Sigma-Aldrich, St. Louis, MO, USA). Mass spectrometer conditions were as follows: capillary voltage: 3.00 kV, sampling cone: 40 V, source offset: 80 V. Ion source temperature was established at 100 °C and desolvation temperature: 200 °C. Cone gas flow was set at 100 L/h and desolvation gas flow—800 L/h.