The main phytonutrients of interest from palm oil are vitamin E, squalene, and phytosterols, the structure of which are given in Figure 1. Waters Viridis HSS C18 SB Column (1.8 µm, 3.0 x 150 mm, p/n: 186006685) was selected for the separation to provide a higher retentivity for these non-polar analytes. Pure palm phytonutrients of squalene, β-sitosterol, stigmasterol, compesterol, α-tocopherol, α-tocomonoenol, α, β, γ, and δ-tocotrienols were analyzed using the ACQUITY UPC2 System coupled with an ACQUITY UPC2 PDA Detector. Figure 2 shows the analysis of various phytonutrient standards using mobile phase compositions of supercritical fluid CO2 and acetonitrile (as the organic modifier) at a flow rate of 1.0 mL/min and UV detection from 190 nm to 400 nm. A total of 10 palm phytonutrients were successfully determined in a single analysis compared to conventional HPLC methods where the determination of these phytonutrients has to be carried out by three different methods. We further tested the performance of the method with analysis of an unsaponifiable palm phytonutrient concentrate, a by-product in the process of palm-based biodiesel production from crude palm oil. These palm phytonutrient concentrates are rich in vitamin E, squalene, and phytosterols and they have received much attention in the palm oil industry due to their potential commercial value. Figure 3 shows the chromatogram from a palm phytonutrients concentrate where the 10 common phytonutrients present in palm oil were successfully separated and detected within a single injection. No lengthy or complicated sample preparation steps were required for this analysis. Palm phytonutrients concentrate samples were dissolved, filtered, and injected into the ACQUITY UPC2 System. Separation of palm phytonutrients using Waters’ ACQUITY UPC2 technology, provides a more efficient, cost saving, and environmentally friendly approach using supercritical CO2 as the mobile phase.
