Data acquisition was performed using MassLynx (version 4.1) for the Synapt G2-S (HILIC-MS) and Analyst (version, 1.6.2) for the QTRAP (HILIC-MS/MS). Peak integration was performed using TargetLynx (version 4.1) and Sciex OS (version 2.1.6) for HILIC-MS and HILIC-MS/MS respectively. The peak asymmetry factor was used to determine the effect of different conditions during method development and was calculated by equation 6 .