Comparative quantitative fatty acid analysis of triacylglycerols using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry and gas chromatography

Abstract

Quantitative analyses of fatty acids from five triacylglycerol products, coconut oil, palm kernel oil, palm oil, lard and cocoa butter, were carried out using two analytical methods: matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and gas chromatography (GC), in an effort to validate the application of MALDI-TOFMS in quantitative fatty acid analysis. For the GC analysis, transmethylated products were used, whereas, for the MALDI-TOF analysis, saponified products were used. Under MALDI-TOF conditions, the acids were detected as sodiated sodium carboxylates [RCOONa + Na](+) consistent with the mode of ionization that was previously reported. Thus, the MALDI-TOF mass spectrum of saponified coconut oil showed the presence of sodiated sodium salts of caprylic acid (7.5 +/- 0.67, m/z 189), capric acid (6.9 +/- 0.83, m/z 217), lauric acid (47.8 +/- 0.67, m/z 245), myristic acid (20.4 +/- 0.51, m/z 273), palmitic acid (9.8 +/- 0.47, m/z 301), linoleic acid (0.9 +/- 0.07, m/z 325), oleic acid (4.8 +/- 0.42, m/z 327) and stearic acid (2.0 +/- 0.13, m/z 329). Saponified palm kernel oil had a fatty acid profile that included caprylic acid (3.5 +/- 0.59), capric acid (4.7 +/- 0.82), lauric acid (58.6 +/- 2.3), myristic acid (20.9 +/- 1.5), palmitic acid (7.2 +/- 1.1), oleic acid (3.8 +/- 0.62) and stearic acid (1.2 +/- 0.15). Saponified palm oil gave myristic acid (0.83 +/- 0.18), palmitic acid (55.8 +/- 1.7), linoleic acid (4.2 +/- 0.51), oleic acid (34.5 +/- 1.5), stearic acid (3.8 +/- 0.26) and arachidic acid (0.80 +/- 0.22). Saponified lard showed the presence of myristic acid (1.5 +/- 0.24), palmitic acid (28.9 +/- 1.3), linoleic acid (13.7 +/- 0.67), oleic acid (38.7 +/- 1.4), stearic acid (12.8 +/- 0.64) and arachidic acid (2.4 +/- 0.35). Finally, for saponified cocoa butter, the fatty acid distribution was: palmitic acid (32.3 +/- 1.0), linoleic acid (2.6 +/- 0.35), oleic acid (34.9 +/- 1.7) and stearic acid (30.3 +/- 1.6). Quantitative gas chromatographic analysis of the corresponding methyl esters from these triacylglycerol products yielded data that were mostly in agreement with the MALDI-TOFMS data. The MALDI-TOF experiment, however, proved to be superior to the GC experiment, particularly with regard to baseline resolution of unsaturated acids. Furthermore, the ability of MALDI-TOFMS to detect low concentrations of fatty acids rendered it more sensitive than the GC methodology.

Qualitative and Quantitative Analysis of Pharmaceutical Compounds by MALDI-TOF Mass Spectrometry

“…Indeed, for molecules lacking basic sites, such as sugars, cationization can be accomplished by the addition of alkali ions . This is also true when using the matrix F20TPP, which is usually mixed with sodium or potassium salts to ionize the analytes of interest. − , We investigated the effect of lithium, sodium, potassium, rubidium, and cesium iodide on the detection limits of lopinavir and ritonavir. Iodide was chosen as counteranion, because the lower lattice energy of alkali iodides compared to other alkali halides results in more free gaseous alkali ions and, thus, higher signal abundances of the cationized analytes .…”

“…These abundant matrix-related peaks seriously hamper the qualitative and quantitative analysis of small molecules. One way to avoid such interference signals is to choose a matrix whose molecular weight is in excess of that of the analyte molecule. , Meso-tetrakis(pentafluorophenyl)porphyrin (F20TPP) is such a high molecular MALDI matrix (MW = 974.6 Da) and has successfully been used for the analysis of various small molecules, for example, poly(ethylene glycol)s, fatty acids, and sugars. − …”

Olive oil from the 79 A.D. Vesuvius eruption stored at the Naples National Archaeological Museum (Italy)

“…Due to matrix interference, MALDI MS is infrequently used for the analysis of relatively small molecules. Nevertheless, under appropriate experimental conditions, MALDI-TOF MS enables robust and reliable analysis of unfractionated FAs and their derivatives, consistent with the GC determination, as well as the simultaneous detection of mono-, di-, and tri-acylglycerols 15 , 16 . The MALDI-TOF MS spectrum of Mann-S1 is shown in Supplementary Material (Fig.…”

Effects of Virgin Coconut Oil and Lauric Acid “With or Without 5-Fluorouracil” on Dimethylhydrazine-Induced Hepatotoxicity in Male Rats

“…It has been reported that the antioxidant activity of VCO is higher than that of refined coconut oil, and its supplementation has beneficial effects on blood lipids by reducing the hepatic lipogenesis and increasing the formation of bile acids [14,15] . In addition, the coconut oil contains high amount of lauric acid (LA), also called n-dodecanoic acid, which is a medium-chain fatty acid that forms monolaurin in the human or animal body [16] . Previous studies have demonstrated many beneficial biological effects of LA [17] .…”