Abstract
For the measurement of prostaglandins several techniques, e.g. bioassay, RIA, HPLC, GC and GC-MS are used. Of these, GC-MS provides the most sensitive and specific methodology. Misinterpretation of data or confusion with other compounds is highly unlikely. Negative ion chemical ionisation mass spectra of methoxime (MO), trimethylsilyl (TMS), pentafluorobenzyl (PFB) derivatives of prostaglandins with CH4 as reagent gas show a fragment ion at m/z (m-PFB)−, which accounts for most of the total ion current. Sensitivity is about a hundred times as high as of electron impact MS. Blood is collected in tubes containing a sodium citrate-indomethacin solution. The plasma is separated and acidified after addition of 2H and 3H standards. Extraction is carried out using a reversed phase Sep-Pak. HPLC separation results in two peaks, the first containing PGE2, TxB2 and 6-k-PGF1α, the second PGF2α. Recovery after HPLC is about 50%. PGE2, TxB2 and 6-k-PGF1α are converted to PFB, MO, TMS derivatives, PGF2α to PFB, TMS derivative. The three MO's are determined in one capillary GC-MS run. Multiple ion detection is carried out by first using the fragment ions m/z 524 and 528 for PGE2, then switching to m/z 614 and 618 for the TxB2 and 6-k-PGF1α fragment ions. Plasma concentrations of 5 healthy volunteers are: PGF2α 3-15, PGE2 2-12, TxB2 7-20 and 6-k-PGF1α 0.5-4 pg/ml. The method is already applied in various experimental and clinical investigations. -Supported by the DFG (Se 263-7).
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Schweer, H., Kammer, J. & Seyeerth, H. Simultaneous determination of prostanoid plasma concentration by GC-negative ion chemical ionisation MS. Pediatr Res 18, 1221 (1984). https://doi.org/10.1203/00006450-198411000-00121
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DOI: https://doi.org/10.1203/00006450-198411000-00121