Microdetermination of prostaglandins and thromboxane B2 by capillary gas chromatography and negative ion chemical ionization mass spectrometry.

Application of dimethyl-n- propylsilyl ( DMnPS ) ether derivatives of prostaglandins (PGs) and thromboxane (TX) B2 pentafluorobenzul ( PFB ) esters of negative ion chemical ionization mass spectrometry ( NICIMS ) was investigated. These derivatives were separated completely within 10 min by the use of a fused-silica capillary column coated with methyl silicone. In NICIMS , all of the DMnPS ether derivatives of PGs and TXB2 PFB esters yielded the characteristic negative ion [M - 181]- which was produced by elimination of PFB from the molecule. The detection limit of the DMnPS ether derivative of PGF2 alpha PFB ester was found to be 200 fg with a signal-to-noise ratio of 5 when monitoring the ion of m/z 653 ([M - 181]-) in the high-resolution mode (R = 2500) using ammonia as a reagent gas. The method was applied to the quantitation of PGE2 and PGF2 alpha in an extract obtained from the plasma of a lung-heart preparation from a dog.