Supercritical Fluid Chromatography with Photodiode Array Detection in the Determination of Fat-Soluble Vitamins in Hemp Seed Oil and Waste Fish Oil.

In the presented study for the first time a new, optimized, fast SFC (supercritical fluid chromatography) method was applied to separate in one run fat-soluble vitamins from waste fish oil, including cis-and trans-retinyl palmitate, cis- and trans-retinyl acetate, retinol, α-tocopherol, β-tocopherol, γ‑tocopherol, δ-tocopherol, ergocalciferol (D₂), cholecalciferol (D₃), cis- and trans-phylloquinone (K₁) and menaquinone-4 (K₂-MK4). Vitamins were baseline separated on an Acquity UPC² (ultra performance convergence chromatography) HSS C18 SB (highly strength chemically modified silica) column within 13 min. The influence of the stationary phase, such as Torus 1-AA (1-aminoanthracene), Torus Diol (high density diol), Torus DEA (diethylamine), BEH (silica with no bonding), BEH-2EP (2-ethylpirydine), CSH Fluoro-Phenyl (silica with fluoro-phenyl groups), column temperature, flow rate and back pressure on the separation of the compounds was described. The application of the modified saponification procedure allowed us to increase concentration in the sample prepared for the analysis of γ‑tocopherol from less than 1% (wt %) to 14% for the first time. In addition, α‑tocopherol, γ‑tocopherol, δ‑tocopherol and retinol were identified in waste fish oil. Vitamin purification and analysis in waste fish oil are reported for the first time here. Due to the short time and effectiveness of the proposed method, it can be easily applied in industrial processes.