Octafluorotoluene as a derivatizing agent for steroids in human plasma.

M H Baker, I Howe, M Jarman, R McCague

Index: Biomed. Environ. Mass Spectrom. 16(1-12) , 211-3, (1988)

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Abstract

The use of octafluorotoluene (OFT) as a versatile gas chromatographic/mass spectrometric derivatizing agent for steroids containing alcoholic, phenolic or alpha, beta-unsaturated keto functions, is described. Two distinct derivatizing schemes can be utilized, involving (method 1) a phase-transfer reaction, employing a two-phase system of CH2Cl2 and N NaOH with n-Bu4NHSO4 as catalyst (suitable for alcoholic and phenolic steroids) and (method 2) a reaction conducted in anhydrous dimethylformamide at 155 degrees C with CsF as base (appropriate for alpha, beta-unsaturated keto steroids). Perfluorotolyl (PFT) ethers and/or enol ethers have thus been generated. The electron impact spectra display abundant high-mass molecular ions where derivatization has occurred at a phenolic or enolic function. An extraction, derivatization and gas chromatographic/mass spectrometric scheme has been devised involving method 2 for the analysis of steroids in human plasma. A preliminary quantitative investigation of the levels of testosterone in plasma has been carried out employing these methods. The anomalously high level found is explained in terms of the presence in plasma of lipid-soluble derivatives of testosterone (probably fatty acid esters) which generate the testosterone bis-OFT derivative under the reaction conditions employed.