2.2.5 HPLC analysis
For HPLC analysis, a series of mixtue of the MO/EMO having varying molar
ratios were prepared as shown in Table 1 . To prepare the
solutions of 0.01 M concentrations, all the samples were dissolved in a
hexane:isopropanol (90:10, v/v) solvent mixture. All samples were
syringe filtered prior to the injection and were analyzed by using HPLC
(Agilent infinity 1200) equipped with a RI detector. The RX-SIL normal
phase column (4.6 mm inner diameter × 250 mm, 5 μm particles) at 35 °C
was employed as stationary phase and a hexane:isopropanol (90:10, v/v)
as mobile phase at a flow rate of 0.4 mL min-1 with
injection volume of 20 μL. In the HPLC chromatogram, the content of MO
and EMO in the mixture was determined by calculating the peak area
percentage corresponding to their respective peaks with respect to the
total area of the chromatogram as shown in Fig 2s (supporting
information)