Free Fatty Acids

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M. A. Ferreira - One of the best experts on this subject based on the ideXlab platform.

  • solid phase microextraction in combination with gc ms for quantification of the major volatile Free Fatty Acids in ewe cheese
    Analytical Chemistry, 2002
    Co-Authors: Olivia Pinho, I. M.p.l.v.o. Ferreira, M. A. Ferreira
    Abstract:

    This work describes a method for quantification of the major Free Fatty Acids of ewe cheese that contribute to its distinct and strongly marked flavor. A headspace SPME method in combination with GC/MS was used for the extraction, identification, and quantification of butanoic, hexanoic, octanoic and decanoic Acids in ewe cheeses. The method used for sample preparation was simple. A fiber coated with 85-μm polyacrylate film was chosen to extract the Free Fatty Acids. To perform a reliable quantification, several factors were taken into consideration for reliable quantification, namely, (i) the influence of addition of water, of an electrolyte or of a hygroscopic salt, on the release of Free Fatty Acids from the matrix; (ii) the linear relationship between the amount of analyte adsorbed by the SPME polymer film and the initial concentration of the analyte in the cheese sample; and (iii) the competition for adsorption by fiber. Water removal with sodium sulfate promoted a more efficient extraction of volati...

  • Solid-phase microextraction in combination with GC/MS for quantification of the major volatile Free Fatty Acids in ewe cheese
    Analytical Chemistry, 2002
    Co-Authors: Olivia Pinho, I. M.p.l.v.o. Ferreira, M. A. Ferreira
    Abstract:

    This work describes a method for quantification of the major Free Fatty Acids of ewe cheese that contribute to its distinct and strongly marked flavor. A headspace SPME method in combination with GC/MS was used for the extraction, identification, and quantification of butanoic, hexanoic, octanoic and decanoic Acids in ewe cheeses. The method used for sample preparation was simple. A fiber coated with 85-microm polyacrylate film was chosen to extract the Free Fatty Acids. To perform a reliable quantification, several factors were taken into consideration for reliable quantification, namely, (i) the influence of addition of water, of an electrolyte or of a hygroscopic salt, on the release of Free Fatty Acids from the matrix; (ii) the linear relationship between the amount of analyte adsorbed by the SPME polymer film and the initial concentration of the analyte in the cheese sample; and (iii) the competition for adsorption by fiber. Water removal with sodium sulfate promoted a more efficient extraction of volatile Free Fatty Acids; biases due to competition or linear range excesses were controlled by choosing the appropriate amount of sample for each ewe cheese. The method of standard additions was used with success for the quantification of Free Fatty Acids. Calibration curves that were constructed for the major short-chain Free Fatty Acids (butanoic, hexanoic, octanoic, and decanoic Acids) spiked into cheese followed linear relationships with highly significant (p < 0.001) correlation coefficients (r > 0.999). Coefficients of variation of

Gordan Kilic - One of the best experts on this subject based on the ideXlab platform.

L T Taylor - One of the best experts on this subject based on the ideXlab platform.

  • Study of UltraHigh Performance Supercritical Fluid Chromatography to measure Free Fatty Acids with out Fatty acid ester preparation
    Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences, 2015
    Co-Authors: Mehdi Ashraf-khorassani, Karen Fountain, Pierre Rainville, Graham Isaac, L T Taylor
    Abstract:

    Most lipids are best characterized by their Fatty Acids which may differ in (a) chain length, (b) degree of unsaturation, (c) configuration and position of the double bonds, and (d) the presence of other functionalities. Thus, a fast, simple, and quantitative analytical technique to determine naturally occurring Free Fatty Acids (FFA) in different samples is very important. Just as for saponified acylglycerols, the determination of FFA's has generally been carried out by high resolution gas chromatography (HRGC). The use of an open tubular capillary column coupled with a flame ionization or mass spectrometric detector provides for both high resolution and quantification of FFA's but only after conversion of all Free Fatty Acids to Fatty acid methyl esters (FAME) or pentafluorobenzyl esters. Unfortunately, volatilization of labile ester derivatives of mono- and poly-unsaturated FFA's can cause both thermal degradation and isomerization of the Fatty acid during HRGC. The employment of a second generation instrument (here referred to as UltraHigh Performance Supercritical Fluid Chromatograph, UHPSFC) with high precision for modified flow and repeated back pressure adjustment in conjunction with sub-2. μm various bonded silica particles (coupled with evaporative light scattering, ELSD, and mass spectrometric, MS, detection) for separation and detection of the following mixtures is described: (a) 31 Free Fatty Acids, (b) isomeric FFA's, and (c) lipophilic materials in two real world fish oil samples. Limits of detection for FFA's via UHPSFC/MS and UHPSFC/ELSD versus detection of FAME's via HRGC/MS are quantitatively compared.

W. M. Coplin - One of the best experts on this subject based on the ideXlab platform.

  • Quantification of Free Fatty Acids in Human Cerebrospinal Fluid
    Neurochemical Research, 2001
    Co-Authors: J. G. Pilitsis, F. G. Diaz, J. M. Wellwood, M. H. O'regan, M. R. Fairfax, J. W. Phillis, W. M. Coplin
    Abstract:

    Free Fatty Acids (FFA) in cerebrospinal fluid (CSF) are well-recognized markers of brain damage in animal studies. Information is limited regarding human CSF in both normal and pathological conditions. Samples of CSF from 73 patients, who had undergone lumbar puncture for medically indicated reasons, came from a core laboratory upon completion of ordered tests. Using high performance liquid chromatography, mean FFA concentrations (μg/L ± SEM) were: arachidonic 26.14 ± 3.44; docosahexaenoic 60.74 ± 5.70; linoleic 105.07 ± 10.98; myristic 160.38 ± 16.17; oleic 127.91 ± 10.13; and palmitic 638.34 ± 37.27. No differences in FFA concentrations were seen with gender, race, age, and/or indication for lumbar puncture. This is the first study to document normal human CSF FFA concentrations in a large series. Further characterization of FFA in pathological conditions may provide markers for evaluating clinical treatments and assisting in prognostication of neurological disease.

Olivia Pinho - One of the best experts on this subject based on the ideXlab platform.

  • solid phase microextraction in combination with gc ms for quantification of the major volatile Free Fatty Acids in ewe cheese
    Analytical Chemistry, 2002
    Co-Authors: Olivia Pinho, I. M.p.l.v.o. Ferreira, M. A. Ferreira
    Abstract:

    This work describes a method for quantification of the major Free Fatty Acids of ewe cheese that contribute to its distinct and strongly marked flavor. A headspace SPME method in combination with GC/MS was used for the extraction, identification, and quantification of butanoic, hexanoic, octanoic and decanoic Acids in ewe cheeses. The method used for sample preparation was simple. A fiber coated with 85-μm polyacrylate film was chosen to extract the Free Fatty Acids. To perform a reliable quantification, several factors were taken into consideration for reliable quantification, namely, (i) the influence of addition of water, of an electrolyte or of a hygroscopic salt, on the release of Free Fatty Acids from the matrix; (ii) the linear relationship between the amount of analyte adsorbed by the SPME polymer film and the initial concentration of the analyte in the cheese sample; and (iii) the competition for adsorption by fiber. Water removal with sodium sulfate promoted a more efficient extraction of volati...

  • Solid-phase microextraction in combination with GC/MS for quantification of the major volatile Free Fatty Acids in ewe cheese
    Analytical Chemistry, 2002
    Co-Authors: Olivia Pinho, I. M.p.l.v.o. Ferreira, M. A. Ferreira
    Abstract:

    This work describes a method for quantification of the major Free Fatty Acids of ewe cheese that contribute to its distinct and strongly marked flavor. A headspace SPME method in combination with GC/MS was used for the extraction, identification, and quantification of butanoic, hexanoic, octanoic and decanoic Acids in ewe cheeses. The method used for sample preparation was simple. A fiber coated with 85-microm polyacrylate film was chosen to extract the Free Fatty Acids. To perform a reliable quantification, several factors were taken into consideration for reliable quantification, namely, (i) the influence of addition of water, of an electrolyte or of a hygroscopic salt, on the release of Free Fatty Acids from the matrix; (ii) the linear relationship between the amount of analyte adsorbed by the SPME polymer film and the initial concentration of the analyte in the cheese sample; and (iii) the competition for adsorption by fiber. Water removal with sodium sulfate promoted a more efficient extraction of volatile Free Fatty Acids; biases due to competition or linear range excesses were controlled by choosing the appropriate amount of sample for each ewe cheese. The method of standard additions was used with success for the quantification of Free Fatty Acids. Calibration curves that were constructed for the major short-chain Free Fatty Acids (butanoic, hexanoic, octanoic, and decanoic Acids) spiked into cheese followed linear relationships with highly significant (p < 0.001) correlation coefficients (r > 0.999). Coefficients of variation of

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