Single-step transesterification with simultaneous concentration and stable isotope analysis of fatty acid methyl esters by gas chromatography-combustion-isotope ratio mass spectrometry

2011 ◽  
Vol 25 (10) ◽  
pp. 1373-1381 ◽  
Author(s):  
Robert J. Panetta ◽  
A. Hope Jahren
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Fatty Acid ◽  
Isotope Ratio ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Isotope Analysis ◽  
Isotope Ratio Mass Spectrometry ◽  
Single Step ◽  
Acid Methyl

Direct ultrasound-assisted methylation of fatty acids in serum for free fatty acid determinations

2010 ◽  
Vol 88 (9) ◽  
pp. 898-905 ◽  
Author(s):  
Liyan Liu ◽  
Ying Li ◽  
Rennan Feng ◽  
Changhao Sun
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Gas Chromatography ◽  
Fatty Acid ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Ultrasonic Waves ◽  
Acid Methyl ◽  
Ultrasound Assisted

A method for simultaneous determination of 16 free fatty acids (FFAs) in serum is described. The method involves conversion of FFAs to fatty acid methyl esters (FAMEs) using the heat of ultrasonic waves followed by gas chromatography and mass spectrometry (GC–MS) analysis. Optimum levels of the variables affecting the yield of FAMEs were investigated. The results indicate that the optimal levels are 55 °C, 60 W, 10% H2SO4/CH3OH, and 50 min. Recoveries ranged from 85.32% to 112.11%, with a detection limit ranging from 0.03 to 0.08 μg mL–1. The linearity, using the linear correlation coefficient, was higher than 0.9914.

scholarly journals Composition Characterization of Fatty Acid Zinc Salts by Chromatographic and NMR Spectroscopic Analyses on Their Fatty Acid Methyl Esters

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Kwang Seo Park ◽  
Yun Ju Kim ◽  
Eun Kyung Choe
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Gas Chromatography ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Gas Chromatography Mass Spectrometry ◽  
Acid Methyl ◽  
Zinc Salts

To implement EU REACH- (Registration, Evaluation, and Authorization of Chemicals-) like chemical legislations in various countries of which the purpose is human and environment safety, the first step is substance identification followed by the hazard and risk assessments. Although both structural and composition identifications are required, the latter can more importantly result in the essential data to fill out the required substance information such as purity and concentrations of constituents, as well as impurities. With fatty acid zinc salts (FAZSs) as an exemplary industrial chemical of which chromatographic and nuclear magnetic resonance (NMR) analyses were impossible due to their insolubility in water and any organic solvents, the composition characterization was tried by preparing their fatty acid methyl esters (FAMEs) using the conc. HCl/methanol/toluene method. This acid-catalyzed methyl esterification was optimized with zinc stearate as a surrogate substance. Gas chromatography-mass spectrometry (GC-MS) and NMR analyses on methyl-esterified products revealed that the optimum conditions were at 90°C for 10 min or 45°C for 30 min with two equivalent HCl as well as at 45°C for 10 min with five equivalent HCl. Almost all zinc stearates were converted into the corresponding fatty acids with 97–99% conversion rates. Free fatty acids (FFAs) were detected in extracted ion chromatograms of pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) in the methyl-esterified products with incomplete conversions of 73∼79%. The optimized conc. HCl/methanol/toluene method of direct one-step reaction from FAZSs was compared with the two-step NaOH saponification/BF3-methanol method after acidic hydrolysis of FAZSs. The mechanism of fatty acid zinc salts into free fatty acids and fatty acid methyl esters was suggested with the evidence of the formation of Zn(OH)2.

Sign in / Sign up

Export Citation Format

Share Document