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At least 505 records · Page 28Linked to original sources
PubMed1986

Determination of prostaglandin E2, prostaglandin F2 alpha and 6-oxo-prostaglandin F1 alpha in urine by gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry: a comparison.

Electron impact fragmentation of methyl ester/methyloxime/trimethylsilyl ether derivatives of prostaglandin E2 and 6-oxo-prostaglandin F1 alpha and the methyl ester/trimethylsilyl ether derivative of prostaglandin F2 alpha is followed by argon collision-activated dissociation in a triple quadrupole mass spectrometer. Daughter ion chromatograms of prostaglandin derivatives show an enormous increase of selectivity compared to the multiple ion detection chromatograms of the same samples in single quadrupole mode.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry of methyl ester/methoxime/trimethylsilyl ether derivatives of prostaglandins.

Electron impact mass spectra of methyl ester/trimethylsilyl ether derivatives of prostaglandin F2 alpha and methyl ester/methoxime/trimethylsilyl ether derivatives of prostaglandin E2, prostaglandin D2, 6-oxo-prostaglandin F1 alpha and 2,3-dinor-6-oxo-prostaglandin F1 alpha are presented. Most of the prostaglandins studied have additionally been 2H-labelled at different sites in order to assign the corresponding fragment ions. Collisionally activated decomposition mass spectra of the most intense parent ions in the high-mass region were taken. High-intensity, prostaglandin-characteristic daughter fragments will allow a reliable quantification of prostaglandins in biological fluids and a reduction of sample clean-up.

Esters↗
PubMed1988

Gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry of methyl ester/methoxime/trimethylsilyl ether derivatives of thromboxanes.

Electron impact mass spectra of methyl ester/methoxime/trimethylsilyl ether derivatives of thromboxane B2 (TxB2) and 2,3-dinor-TxB2 and methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 are presented. Additionally, the derivatives of (2H4)-thromboxanes and methyl ester (2H3)-methoxime/trimethylsilyl ether derivatives of TxB2 and 2,3-dinor-TxB2 and (2H3)-methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 were investigated. Collision-induced dissociation mass spectra of the most intense parent ion in the high-mass region were taken. Collisionally activated decomposition mass spectra of the [C(12)-C(20)]+ ion of TxB2 and 2,3-dinor-TxB2 show an intense but not specific daughter ion, whereas the collision-induced dissociation mass spectrum of the [M-(C(16)-C(20)]+ ion of 11-dehydro-TxB2 results in the formation of numerous daughter ions.

Esters↗
PubMed1991

The analysis of trenbolone and the human urinary metabolites of trenbolone acetate by gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry.

The electron impact mass spectrometric properties of trimethylsilyl ether and fluoroacyl ester derivatives of trenbolone, combined or not combined with a methoxime group, are presented. Some derivatization problems were observed and were due to the formation of enol derivatives at the 3C-position in several tautomeric forms, which in their turn were not stable and lost two or four hydrogens under the conditions studied. The enolization could be minimized by carefully selecting the reaction conditions or could be prevented by the introduction of a methoxime group at the 3C-position. The limits of detection and identification of the methoxime heptafluorobutyryl ester and the methoxime trimethylsilyl ether derivative of trenbolone were determined using a mass selective detector in the electron impact mode and a triple-stage quadrupole in the methane positive chemical ionization mode. Selected reaction monitoring in tandem mass spectrometry did not improve the limit of detection, but because of the gain in selectivity did improve the limit of identification. The glucuronides of trenbolone and epitrenbolone could be identified in three urine specimens out of 200 samples in routine doping control.

Fluoroacetates↗