Gas chromatographic—mass spectrometric studies of long chain hydroxy acids.—III.1 The mass spectra of the methyl esters trimethylsilyl ethers of aliphatic hydroxy acids. A facile method of double bond location

1968 ◽  
Vol 1 (4) ◽  
pp. 593-611 ◽  
Author(s):  
G. Eglinton ◽  
D. H. Hunneman ◽  
A. McCormick
Keyword(s):  
Double Bond ◽  
Mass Spectra ◽  
Methyl Esters ◽  
Mass Spectrometric ◽  
Hydroxy Acids ◽  
Trimethylsilyl Ethers ◽  
Long Chain ◽  
Chromatographic Mass

Gas chromatographic—mass spectrometric studies of long chain hydroxy acids—II

Tetrahedron ◽  
1968 ◽  
Vol 24 (18) ◽  
pp. 5929-5941 ◽  
Author(s):  
G. Eglinton ◽  
D.H. Hunneman ◽  
K. Douraghi-Zadeh
Keyword(s):  
Mass Spectrometric ◽  
Hydroxy Acids ◽  
Long Chain ◽  
Chromatographic Mass

Gas chromatographic–mass spectrometric detection of 2- and 3-hydroxy fatty acids as methyl esters from soil, sediment and biofilm

2003 ◽  
Vol 783 (2) ◽  
pp. 443-451 ◽  
Author(s):  
M.M. Keinänen ◽  
L.K. Korhonen ◽  
P.J. Martikainen ◽  
T. Vartiainen ◽  
I.T. Miettinen ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Methyl Esters ◽  
Mass Spectrometric ◽  
Mass Spectrometric Detection ◽  
Hydroxy Fatty Acids ◽  
Soil Sediment ◽  
Chromatographic Mass

Gas-Liquid Chromatographic-Mass Spectrometric Confirmation of Endosulfan and Endosulfan Sulfate in Apples and Carrots

1981 ◽  
Vol 64 (5) ◽  
pp. 1208-1210
Author(s):  
Perry S Wilkes
Keyword(s):  
Mass Spectra ◽  
Chemical Ionization ◽  
Mass Range ◽  
Mass Spectrometric ◽  
Chromatographic Retention ◽  
Gas Liquid Chromatography ◽  
Endosulfan Sulfate ◽  
Gasliquid Chromatography ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract A gas-liquid chromatography-mass spectrometric (GLC-MS) procedure is described for the confirmation of endosulfan I, endosulfan II, and endosulfan sulfate in apples and carrots. After extraction, cleanup, and determination by electron capture gasliquid chromatography using current AOAC methodology, residues are confirmed by GLC-MS. The chemical ionization (CI) mode is used with methane as a reagent gas. Each residue is confirmed by a scan of only 4 regions of its mass spectrum rather than the full mass range. The 4 mass regions for the 2 endosulfan isomers are 274-280, 340-346, 368-374, and 404-412 atomic mass units (amu). For endosulfan sulfate, the mass regions are 286-294, 322-330, 384-392, and 420-428 amu. Four ions and their chlorine isotopic distributions are detected for each compound by this scanning technique. This method was developed by using carrots and apples to which had been added 0.1 ppm (50% of the current legal tolerance on carrots) of each of the 3 pesticides. The gas chromatographic retention times and the mass spectra of the 4 mass regions specified for the 3 pesticides were compared to those of reference standards injected under identical GLC-MS conditions and were used as the basis for confirming identity of the 3 compounds.

scholarly journals Improved Method for Gas Chromatographic–Mass Spectrometric Analysis of 1-13C-labeled Long-Chain Fatty Acids in Plasma Samples

2002 ◽  
Vol 48 (6) ◽  
pp. 906-912 ◽  
Author(s):  
José M Hernández-Pérez ◽  
Eduard Cabré ◽  
Lourdes Fluvià ◽  
Ágata Motos ◽  
Cruz Pastor ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Isotopic Ratio ◽  
Internal Standard ◽  
Mass Spectrometric ◽  
Spectrometric Analysis ◽  
Calibration Curves ◽  
Long Chain ◽  
Chromatographic Mass

Abstract Background: Gas chromatographic–mass spectrometric (GC/MS) tracking of stable-isotope-labeled substrates is useful in metabolic studies. However, GC/MS analysis of long-chain fatty acid methyl esters yields results that mostly depend on their concentration in the system. We describe a protocol aimed to obviate this and other drawbacks in plasma [1-13C]palmitic and [1-13C]oleic acid measurements. Methods: Lipoproteins were separated by sequential ultracentrifugation. Free or esterified heptadecanoic acid was used as internal standard. Fatty acids were derivatized to trimethylsilyl (TMS) esters. GC separation was in isothermal mode at 210 °C for 27 min. For both TMS-palmitate and TMS-oleate, M and [M + 1] signals were simultaneously acquired with a dual acquisition program in single-ion monitoring mode. Calibration mixtures containing increasing amounts of labeled fatty acids were prepared gravimetrically to construct calibration curves for isotopic enrichment. Likewise, five calibration curves (for increasing concentrations) were constructed for each fatty acid; this allowed selection of the most appropriate curve for the concentration in a plasma sample. Results: Oleic acid-TMS ester was clearly separated from that of its stereoisomer, elaidic acid. Within a 10-fold concentration range, the isotopic ratio was independent on the amount of the analyte in the sample, with a maximum uncertainty of 0.34% in terms of molar percent excess. In addition, the within- and between-day imprecision (CV) of the method was <1%. Conclusion: Results obtained with this method are independent of concentration and sufficiently precise for tracking 1-13C-labeled palmitic and oleic acids in biological samples

Comparison of Gas Chromatographic/Mass Spectrometric and Liquid Chromatographic/Mass Spectrometric Methods for Confirmation of Coumaphos and Its Oxygen Analog in Eggs and Milk

1983 ◽  
Vol 66 (6) ◽  
pp. 1358-1364
Author(s):  
Kevin D White ◽  
Zhao Min ◽  
William C Brumley ◽  
Richard T Krause ◽  
James A Sphon
Keyword(s):  
Mass Spectra ◽  
Chemical Ionization ◽  
Negative Ions ◽  
Mass Spectrometric ◽  
Ionization Mass ◽  
Organophosphate Insecticide ◽  
Ion Detection ◽  
Oxygen Analog ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract A comparison of a liquid chromatographic (LC)/mass spectrometric (MS) procedure for confirming coumaphos, an organophosphate insecticide, and its oxygen analog in milk and eggs with a capillary gas chromatographic (GO/MS method is presented. For the confirmation of coumaphos and its oxygen analog, multiple ion detection of both positive and negative ions from the chemical ionization mass spectra was used. Samples of milk and eggs fortified with the 2 compounds at the 0.1,0.01, and 0.005 ppm levels were analyzed. The major finding is the relatively greater efficiency of the LC/MS interface compared with the GC/MS capillary injector.

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