Profiling of triacylglycerols in plant oils by high-performance liquid chromatography-atmosphere pressure chemical ionization mass spectrometry using a novel mixed-mode column.

Abstract

In this investigation, a rapid and high-throughput method for profiling of TAGs in plant oils by liquid chromatography using a single column coupled with atmospheric pressure chemical ionization (APCI) mass spectrometry was reported. A novel mixed-mode phenyl-hexyl chromatographic column was employed in this separation system. The phenyl-hexyl column could provide hydrophobic interactions as well as π-π interactions. Compared with two traditionally columns used in TAG separation - the C18 column and silver-ion column, this column exhibited much higher selectivity for the separation of TAGs with great efficiency and rapid speed. By comparison with a novel mix-mode column (Ag-HiSep OTS column), which can also provide both hydrophobic interactions as well as π-π interactions for the separation of TAGs, phenyl-hexyl column exhibited excellent stability. LC method using phenyl-hexyl column coupled with APCI-MS was successfully applied for the profiling of TAGs in soybean oils, peanut oils, corn oils, and sesame oils. 29 TAGs in peanut oils, 22 TAGs in soybean oils, 19 TAGs in corn oils, and 19 TAGs in sesame oils were determined and quantified. The LC-MS data was analyzed by barcodes and principal component analysis (PCA). The resulting barcodes constitute a simple tool to display differences between different plant oils. Results of PCA also enabled a clear identification of different plant oils. This method provided an efficient and convenient chromatographic technology for the fast characterization and quantification of complex TAGs in plant oils at high selectivity. It has great potential as a routine analytical method for analysis of edible oil quality and authenticity control.