The synthesis of a new silylating reagent, tert.-butylpentafluorophenylmethylchlorosilane (tert.-buflophemesyl chloride) is described. The reagent forms volatile derivatives of alcohols, phenols, carboxylic acids, thiols and amines which are suitable for gas chromatography with electron-capture detection. The tert.-buflophemesyl derivatives are many-fold more stable towards hydrolysis than the flophemesyl derivatives to conditions such as partitioning between organic solvents and acid or base, thin-layer chromatography and column chromatography. The mass spectra of the derivatives show characteristics of both the flophemesyl and tert.-butyldimethylsilyl derivatives and are suitable for compound identification.
