Rapid quantitative determination of triglycerides in edible oils by matrix-assisted laser desorption/ionisation Fourier transform ion cyclotron resonance mass spectrometry using pencil graphite combined with 2,5-dihydroxybenzoic acid as matrix

摘要

A rapid quantitative method based on matrix-assisted laser desorption/ionisation Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FT-ICR-MS) was established for the repeatable determination of triglycerides in edible oil. In this method, pencil graphite combined with 2,5-dihydroxybenzoic acid (DHB) was used as a matrix. The method was applied to determine the presence of animal fat adulterants in vegetable oil by quantitative analysis of the differences between the MS peaks of vegetable oil and animal fat. A solution of the edible oil sample and DHB matrix was spotted on a MALDI target plate coated with 2B pencil graphite. The characteristic profiles of triglycerides in edible oil were then quantitatively determined by MALDI-FT-ICR-MS, which provided the MS spectra of edible oils and reproducible MS peak intensity. Moreover, MS/MS can be used to qualitatively determine the molecular structure of triglycerides in edible oil. The presence of 10% lard or mutton fat in corn oil was directly recognised. Results suggested that MALDI FT-ICR-MS is a suitable method for the quantitative analysis of triglycerides and the identification of adulterants in edible oils. (C) 2018 Published by Elsevier B.V.