Evaluation of methylations and external/internal standard quantification of lipids using gas chromatography-mass spectrometry

2017 ◽  
Vol 9 (3) ◽  
pp. 419-426
Author(s):  
Yang Qin ◽  
Wang Shunhe ◽  
Chen Haiqin ◽  
Gu Zhennan ◽  
Zhang Hao ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Fatty Acid ◽  
Standard Method ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Internal Standard Method ◽  
Chromatography Mass Spectrometry ◽  
External Standard Method ◽  
External Standard

A method for rapid and efficient fatty acid derivatization was proposed and as for the quantification, it was found that the results of the external standard method were as good as those of the internal standard method.

scholarly journals Determination of Bitertanol Residues in Strawberries by Liquid Chromatography with Fluorescence Detection and Confirmation by Gas Chromatography/Mass Spectrometry

1998 ◽  
Vol 81 (6) ◽  
pp. 1252-1256 ◽  
Author(s):  
Yoshie Yamazaki ◽  
Takahiro Ninomiya
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Ethyl Acetate ◽  
Fluorescence Detection ◽  
Solid Phase ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Internal Standard Method ◽  
Chromatography Mass Spectrometry

Abstract A simple and rapid method was developed for determining bitertanol residues in strawberries. Bitertanol was extracted from samples with ethyl acetate. Bitertanol acetate was added prior to extraction as a surrogate standard. The ethyl acetate extract was cleaned up by passing through tandem solid-phase extraction columns consisting of anion-exchange (SAX) and aminopropyl (NH2) bonded silica. The eluate was evaporated to dryness and reconstituted with methanol. Bitertanol residues were determined by liquid chromatography with fluorescence detection. Recoveries at 4 fortified levels (0.05,0.25,0.5, and 1.0 (µg/g), calculated by the internal standard method, ranged from 92.1 to 99.1 %, with coefficients of variation ranging from 0.3 to 4.0%. The detection limit was 0.01 µg/g. Of 25 commercial strawberry samples analyzed for bitertanol residues, 5 contained bitertanol residues at concentrations ranging from 0.02 to 0.51 µg/g. Positive samples were confirmed by gas chromatography/mass spectrometry with mass-selective detection (m/z 170 and 168).

Specific estimation of 24,25-dihydroxyvitamin D in plasma by gas chromatography-mass spectrometry.

1984 ◽  
Vol 30 (7) ◽  
pp. 1193-1198 ◽  
Author(s):  
R D Coldwell ◽  
D J Trafford ◽  
H L Makin ◽  
M J Varley ◽  
D N Kirk
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Plasma Vitamin ◽  
Vitamin D Metabolites ◽  
Dihydroxyvitamin D3 ◽  
Dihydroxyvitamin D ◽  
Chromatography Mass Spectrometry ◽  
24,25 Dihydroxyvitamin D3

Abstract This paper describes a specific mass-fragmentographic method, involving a stable-isotope-labeled internal standard, for measurement of 24,25-dihydroxyvitamin D in human plasma. Vitamin D metabolites were rapidly extracted from plasma by using Sep-Pak C18 cartridges and separated into fractions on Sep-Pak SIL cartridges. The polar fraction, containing the dihydroxylated metabolites, was further purified by "high-performance" liquid chromatography on Zorbax SIL. The fraction containing 24,25-dihydroxyvitamin D was collected, evaporated, and converted to the 24:25-cyclic n-butyl boronate-3-trimethylsilyl ether derivative before analysis by gas chromatography-mass spectrometry. The intensity of the mass fragment (m/z 449, m/z 455 for the hexadeuterated internal standard) arising from the loss of one of the angular methyls and the 3-silanol group [( M-90-15]+) was monitored. The minimum limit of detection for this method is about 0.1 microgram/L. Inter- and intra-assay reproducibility was acceptable, and analytical recovery of added 24,25-dihydroxyvitamin D3 over the concentration range 1.0 to 5.0 micrograms/L was quantitative. Concentrations of 24,25-dihydroxyvitamin D3 in plasma of 21 apparently healthy volunteers were between 0.55 and 5.39 micrograms/L, higher values being obtained after prolonged exposure to the sun. No 24,25-dihydroxyvitamin D2 could be detected in any plasma sample examined.

Determination of Pyrantel in Swine Liver by Flame Ionization Gas Chromatography and Confirmation by Gas Chromatography /Mass Spectrometry

1990 ◽  
Vol 73 (6) ◽  
pp. 883-886
Author(s):  
Susan S.C Tai ◽  
Nancy Cargile ◽  
Charlie J Barnes ◽  
Philip Kijak
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Tissue Samples ◽  
Flame Ionization ◽  
Chromatography Mass Spectrometry ◽  
Ionization Method ◽  
Swine Liver

Abstract During an evaluation of the gas chromatography/mass spectrometry (GC/MS) confirmatory procedure of Lynch and Bartoluccl for pyrantel residues in swine tissues, we developed a GC flame Ionization method for quantltatlng pyrantel residues In extracts of swine liver. The method was subjected to trial principally In the laboratories of Biospherics, Inc., using control liver, fortified control liver, and Incurred liver tissue samples. Although the method does not meet all of the current Food and Drug Administration criteria, it compares favorably to the official determinative method. Portions of the same extract can be used for quantitation and for GC/MS confirmation, true recoveries appear to be slightly higher, and an internal standard Is not required. The precision of this method equals or exceeds that of the official determinative method.

Sign in / Sign up

Export Citation Format

Share Document