Addendum to “The vaporization enthalpies and vapor pressures of a series of fatty acids methyl esters for C18, C21 to C23, C25 to C29 by correlation gas chromatography” [Thermochim. Acta 424 (2004) 111–121]

2007 ◽  
Vol 463 (1-2) ◽  
pp. 93-94 ◽  
Author(s):  
James S. Chickos ◽  
Hui Zhao ◽  
Gary Nichols
Keyword(s):  
Fatty Acids ◽  
Gas Chromatography ◽  
Methyl Esters ◽  
Vapor Pressures ◽  
Correlation Gas Chromatography

scholarly journals Comparison of Two Derivatization Methods for the Analysis of Fatty Acids andTransFatty Acids in Bakery Products Using Gas Chromatography

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jumat Salimon ◽  
Talal A. Omar ◽  
Nadia Salih
Keyword(s):  
Fatty Acids ◽  
Gas Chromatography ◽  
Methyl Esters ◽  
Correlation Coefficients ◽  
Bakery Products ◽  
Trimethylsilyl Diazomethane ◽  
Acid Catalyzed ◽  
High Level ◽  
Level Of Agreement

Two different procedures for the methylation of fatty acids (FAs) andtransfatty acids (TFAs) in food fats were compared using gas chromatography (GC-FID). The base-catalyzed followed by an acid-catalyzed method (KOCH3/HCl) and the base-catalyzed followed by (trimethylsilyl)diazomethane (TMS–DM) method were used to prepare FA methyl esters (FAMEs) from lipids extracted from food products. In general, both methods were suitable for the determination ofcis/transFAs. The correlation coefficients (r) between the methods were relatively small (ranging from 0.86 to 0.99) and had a high level of agreement for the most abundant FAs. The significant differences (P=0.05) can be observed for unsaturated FAs (UFAs), specifically for TFAs. The results from the KOCH3/HCl method showed the lowest recovery values (%R) and higher variation (from 84% to 112%), especially for UFAs. The TMS-DM method had higherRvalues, less variation (from 90% to 106%), and more balance between variation and %RSD values in intraday and interday measurements (less than 4% and 6%, resp.) than the KOCH3/HCl method, except for C12:0, C14:0, and C18:0. Nevertheless, the KOCH3/HCl method required shorter time and was less expensive than the TMS-DM method which is more convenient for an accurate and thorough analysis of richcis/transUFA samples.

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 Vaporization Enthalpies and Vapor Pressures of the Major Components of Opopanax Oil, α-Santalene, cis α Bisabolene, cis α-Bergamotene,

2021 ◽  
Author(s):  
Dustin Barton ◽  
James S Chickos
Keyword(s):  
Gas Chromatography ◽  
Vapor Pressure ◽  
Elevated Temperatures ◽  
Vapor Pressures ◽  
Polycyclic Hydrocarbons ◽  
Ambient Temperatures ◽  
Correlation Gas Chromatography ◽  
Existing Data

Abstract The vapor pressures and vaporization enthalpies of the major components of opopanax oil, a medicinal that has been in use since biblical times, are evaluated by correlation gas chromatography. Two sets of hydrocarbon standards are used, n-alkanes and a mixture of cyclic and polycyclic hydrocarbons. Two of the oil’s sesquiterpene components, evaluated in a previous study, were used both as standards and also as targets. Their use as targets was in an effort to confirm both their identity in the oil and the reproducibility of their properties. All correlations produce reproducible vaporization enthalpies and vapor pressures at ambient temperatures. At elevated temperatures, the use of the two different sets of standards resulted in some divergence in vapor pressure. Experiments are described aimed at attenuating this divergence. The results are compared to existing data.

scholarly journals Performance of GC-MS analysis for differentiation of various types of flour by creating dendrogram of liposoluble extract

2012 ◽  
Vol 18 (4-1) ◽  
pp. 555-561 ◽  
Author(s):  
Djura Vujic ◽  
Marijana Acanski ◽  
Marija Bodroza-Solarov ◽  
Nikola Hristov ◽  
Milica Krunic
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Cluster Analysis ◽  
Gas Chromatography ◽  
Methyl Oleate ◽  
Methyl Palmitate ◽  
Methyl Esters ◽  
Fatty Acids Composition ◽  
Different Types ◽  
Small Grains

Gas chromatography with mass spectrometry was used for performing a qualitative analysis of liposoluble flour extract made of different types of small grains (bread wheat, barley and triticale). The results show that the dominant methyl-esters of fatty acids composition is same for all samples, but the percentage of their representation in various types of small grains is different. Transesterification reagent was TMSH (Trimethylsulfonium hydroxide, 0.2M in methanol). With transesterification reaction fatty acids from acilglycerol esterifyed to methyl-esters. In all extract analyzed methyl linoleate predominated, followed by methyl palmitate, methyl oleate and methyl stearate in decreasing order. The following tests cluster analysis was used for the comparison of the liposoluble flour extract different types of small grains.

scholarly journals Homogenity of oil and sugar components of flour amaranth investigated by GC-MS

2015 ◽  
Vol 21 (1-1) ◽  
pp. 71-76
Author(s):  
Djordje Psodorov ◽  
Marijana Acanski ◽  
Djura Vujic ◽  
Jovana Brkljaca ◽  
Dragan Psodorov
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Gas Chromatography ◽  
Methyl Esters ◽  
Soluble Sugars ◽  
Soluble Carbohydrates ◽  
Three Samples ◽  
Hexane Extracts ◽  
Ethanol Extracts ◽  
Ethanol Ethanol

Gas chromatography with mass spectrometry (GC-MS) was used for performing a qualitative analysis of liposoluble and hydrosoluble flour extracts of three genotypes of Amaranthus sp. All three samples were first defatted with hexane. Hexane extracts were used for the analysis of fatty acids of lipid components. TMSH (Trimethylsulfonium hydroxide, 0.2M in methanol) was used as the transesterification reagent. With transesterification reaction, fatty acids were esterified from acilglycerol to methyl-esters. Defatted flour samples were dried in the air and then extracted with ethanol. Ethanol extracts were used for the analysis of soluble carbohydrates. TMSI (trimethylsilylimidazole) was used as a reagent for the derivatization of carbohydrates into trimethylsilylethers. The results show that the dominant methyl-esters of fatty acids are very similar in all the three samples. Such a similarity was not detected in the analysis of soluble sugars. The following test cluster analysis was used for the comparison of liposoluble and hydrosoluble flour extracts of three genotypes of Amaranthus sp.

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