Determination of Fatty Acids in Beef by Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry

Abstract

A method was developed to separate, identify, and quantify 28 fatty acids of potential health relevance using liquid chromatography/electrospray ionizationmass spectrometry (LC/ESI-MS). Optimization of the experimental factors enabled baseline separation of the fatty acids including three pairs of closely related fatty acid isomers (C18:3n-3 and C18:3n-6; C18:1 and C18:1 t; and C20:3n-3 and C20:3n-6) that are challenging to separate. The limits of detection ranged from 0.01 to 0.26 mg L −1 for the 28 fatty acids, and average recovery (mean, n =4) was found to be 102 ±12 %. In addition, the proposed method was validated using a quality control standard mix of fatty acids which yielded acceptable precision and accuracy. Fatty acid concentrations in conventional grain-fed and organic grass-fed beef were determined, and the results show that grass-fed beef have a lower omega-6 to omega-3 ratio (1.6-2.8) compared to grain-fed beef (9.3-13.5). Principal component analysis (PCA) was applied on the resulting data to find correlations between significant fatty acid composition and the diet of beef samples.

Structural Elucidation of 3-Nitrophenylhydrazine Derivatives of Tricarboxylic Acid Cycle Acids and Optimization of Their Fragmentation to Boost Sensitivity in Liquid Chromatography-Mass Spectrometry

“…Reversed-phase chromatography and mixed-mode chromatography have been the traditional choices for separation and screening of underivatized medium-to long-chain fatty acids in LC-MS due to their low polarity nature [25,27,28]. However, their derivatization to less polar species helps to enhance screening coverage in LC-MS-based applications that require separation of metabolites with wide range of polarities [29,30].…”

Mixed-mode chromatography-mass spectrometry enables targeted and untargeted screening of carboxylic acids in biological samples

“…Only a few studies were reported on baseline separation of isomers such as a-linolenic acid (18:3n À 3) and g-linolenic acid (18:3n À 6) by using LC; moreover, total separation requires either long analysis under isocratic conditions 24 and/or use of a chiral stationary phase. 25 The developed method allowed separation of some fatty acids commonly found in human plasma, where 23 fatty acids were identied with oleic acid being the most abundant fatty acid found in plasma and cells.…”

Direct quantitation and characterization of fatty acids in salmon tissue by condensed phase membrane introduction mass spectrometry (CP-MIMS) using a modified donor phase

“…A popular method of FA analysis is the derivatization of FAs into fatty acid methyl esters (FAME) [18]. MS methods for the analysis of lipids have also been developed for high performance and ultra high performance liquid chromatography HPLC/UHPLC-MS [8,[19][20][21][22] and supercritical fluid chromatography SFC-MS [2]. Many of these methods utilize tandem mass spectrometric techniques (MS/MS) to enhance both sensitivity and selectivity as well as increase the amount of structural information that can be obtained during analysis [15].…”