DETERMINATION OF 9-ALPHA,11-BETA-PROSTAGLANDIN F2 IN HUMAN URINE AND PLASMA BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

Sensitive and specific assay methods for 9 alpha,11 beta-prostaglandin F-2 (9 alpha,11 beta-PGF(2)) by gas chromatography-mass spectrometry with electron impact ionization are described. The mass spectrometric assay for 9 alpha,11 beta-PGF(2) was based on the use of the methyl ester-dimethylisopropylsilyl ether derivative, and pentadeuterated PGF(2 alpha) as a convenient internal standard. The calibration graph for 9 alpha,11 beta-PGF(2) was linear from 5 pg to 100 ng for both the standard and spiked biological samples. The limit of detection was 50 pg/ml for urine and 25 pg/ml for plasma (signal-to-noise ratio = 2.3). The method was applied to the determination of 9 alpha,11 beta-PGF(2) in urine and plasma samples from patients with bronchial asthma.