Abstract: This study aimed to establish a simple, rapid and accurate analytical method for the determination of oxidized triacylglycerol polymers (TGP) in oils and fats. Non-polar components (Non-PC) and polar components (PC), including oxidized triacylglycerol oligomers (TGO), oxidized triacylglycerol dimers (TGD), oxidized triacylglycerol monomers (ox-TGM), diacylglycerls (DG) and free fatty acids (FFA), were separated by high performance liquid chromatography with two sequential columns (silica gel column connected to Phenogel column) and detected by an evaporative light scattering detector. The peak area normalization method was used to quantitate TGP using DG as external standard. The eluent used was a gradient mixture of petroleum ether (A) and tetrahydrofuran (B). Elution was performed at a solvent flow rate of 0.7 mL/min in the following linear gradient mode: 0 min, 5% B; 20 min, 15% B; 30 min, 30% B; and 35 min, 5% B, and the analytical time was 50 min. The results showed that good separation of the above compounds was achieved. The method exhibited a good linearity with a correlation coefficient (R2) of 0.999 5. The limit of detection (LOD) of TGD was 156 mg/L, and the limit of quantitation (LOQ) was 267 mg/L. The recoveries of DG spiked samples were between 95% and 99% with relative standard deviation (RSD) of less than 2%. Moreover, the method presented good repeatability with RSD of less than 3%. This method could allow accurate quantification of TGP in oils and fats within 1 h with simple operation and without using extra experimental materials.

Key words: oxidized triacylglycerol polymer, polar component, two sequential columns, high performance liquid chromatography