Determination of carotene, tocopherols and tocotrienols in residue oil from palm pressed fiber using pressurized liquid extraction-normal phase liquid chromatography

Pressurized liquid extraction (PLE) along with normal phase liquid chromatography (NPLC) is evaluated as a new approach for the determination of β-carotene and Vitamin E isomers in residue oil obtained from palm pressed fiber (PPF). The relative extraction recoveries obtained by optimized PLE were found to be equivalent (∼100%) to conventional Soxhlet extraction. Optimized PLE was obtained (5 g of sample, 80 °C, 1500 psi, 2× 10 min static extractions with flush volume 50%) combined with NPLC system. Typical extractions give 3.7-4.0 mg ml−1 of Vitamin E isomers and β-carotene of 3.3-3.5 mg ml−1, which is similar to or greater than classical Soxhlet extraction with n-hexane or chloroform. The new developed method demonstrated an acceptable performance with good efficiency in terms of total extraction time, total solvent usage, total β-carotene and Vitamin E isomers contents as well as exceptional method repeatability.