Analysis of Triglycerides in Cooking Oils Using MALDI-TOF Mass Spectrometry and Principal Component Analysis

Abstract

Triglycerides are composed of three esterified fatty acids bound to a glycerol backbone, and are the main component of several types of cooking oils. They are biologically important molecules in that they serve as an important source of energy. The analysis of lipids using other forms of mass spectrometry has proved difficult due to the large degree of fragmentation observed in the ionization process, indicating the importance of developing a new method. In this study, the analysis of triglycerides in 9 common cooking oils was conducted using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Using 2,5-dihydroxybenzoic acid (2,5-DHB) and 9-aminoacridine (9-aa) as a matrix, intact triglycerides were successfully identified in all 9e cooking oils with little fragmentation. Principal component analysis (PCA), a technique used to identify underlying similarities and differences in a data set, was used in conjunction with MALDI-TOF mass spectrometry. The application of PCA to the mass spectral data obtained from the MALDI-TOF mass spectrometer allowed for further comparison of the underlying properties and components of each cooking oil. The results from PCA show noticeable differences in particular oils, and the MALDI method was also able to discriminate between these differences. This MALDI method can potentially be used to identify unknown oil samples or provide quality control in commercial settings.