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

Abstract

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.

Mass Spectrometric Fragmentation of Trimethylsilyl and Related Alkylsilyl Derivatives

“…Other papers of interest on prostaglandins include those by Schweer et al () (PGF 2α , PGE 2 , PGD 2 , 6‐oxo‐PGF 1α , and 2,3‐di‐ nor ‐6‐oxo‐PGF 1α , methyl ester/methyloxime/TMS derivatives) and Schweer et al () (same compounds, pentafluorobenzyl ester (PFB)/methyloxime/TMS derivatives).…”

Direct solid-phase isolation and oximation of prostaglandin E2 from plasma and quantitation by gas chromatography with mass spectrometric detection in the negative-ion chemical ionization mode

“…Sample preparation of prostaglandins for high-sensitivity analysis by gas chromatography (GC) with detection by mass spectrometry (MS) in the negative-ion chemical ionization (NICI) mode requires isolation from an aqueous matrix, ox-imation (excepting the F series, which contain no carbonyls), esterification with pentafluorobenzyl bromide ((PFB)Br), and finally silylation. Esterification and silylation are rapid and simple (1)(2)(3)(4)(5)(6)(7). Procedures for oximation, however, are more complex, and two general reactions conditions have been reported: derivatization in aqueous medium (8) and reaction in pyridine (1)(2)(3)(4)(5)(6)(7).…”

“…Esterification and silylation are rapid and simple (1)(2)(3)(4)(5)(6)(7). Procedures for oximation, however, are more complex, and two general reactions conditions have been reported: derivatization in aqueous medium (8) and reaction in pyridine (1)(2)(3)(4)(5)(6)(7).…”

“…Despite reports of a simple and rapid oximation of prostaglandins, current methods for the determination of these analytes require, first, isolation of analytes from the matrix and, then, reaction of the residue at 50-60 °C for 1 h (1,2) or at ambient temperature with an overnight reaction time (2)(3)(4)(5)(6)(7). Several procedures recommend anhydrous conditions for oximation (3,4) as do the instructions for use of commercial methoximating reagents (4).…”

“…Pyridine is a hygroscopic solvent, and such conditions are not easily maintained. After oximation, pyridine is evaporated, and some procedures require further purification of analytes by partitioning the reaction mixture between acidified water and organic solvent (3) or 0003-2700/91Z0363-1536502.50/0 © 1991 American Chemical Society by column chromatography (5,6).…”