New derivatives of prostaglandin A 1 and specific detection of prostaglandin A's and 19‐hydroxylated prostaglandin A's in human semen

The derivatization of prostaglandins of the A series with 1:1 mixtures of bis‐(trimethylsily)trifluoroacetamide and nitrogen‐containing non‐aromatic heterocyclics such as piperidine, pyrrolidine, morpholine and hexamethylenimine (1–4 h at 60–70 °C) gives new types of derivatives, designated as 11‐heterocycle, 9‐enol PGA (TMS) 3 . These derivatives show very simplified and characteristic mass spectral patterns strikingly dominated by a common [M‐173] + fragment ion and easily detectable by selected ion monitoring. This feature allows the concurrent analytical detection of both prostaglandin A's and 19‐hydroxy prostaglandin A's in biological samples. In this case 2 ml samples of human semen were extracted by direct ultrafiltration on a Pellicon membrane with a nominal molecular weight limit of 1000. The prostaglandins in the ≃ 1.6 ml of ultrafiltrate thus obtained were recovered in ethyl acetate, derivatized as indicated above and detected by monitoring of the corresponding [M–173] + ions.