USE OF MICROWAVE IRRADIATION FOR RAPID SYNTHESIS OF PERFLUOROOCTANOYLDERIVATIVES OF FATTY ALCOHOLS, A NEW DERIVATIVE FOR GAS-CHROMATOGRAPHY MASS-SPECTROMETRIC AND FAST-ATOM-BOMBARDMENT MASS-SPECTROMETRIC STUDY

Structural analyses of fatty alcohols as acetate, trifluoroacetate and trimethylsilyl derivatives are frequently used in lipid biochemistry. Those derivatives produce molecular ions (m/z) < 400. Perfluorooctano yl derivatives of fatty alcohols which can produce ions in the range o f 600-700 (m/z) have never been studied before. We prepared perfluoroo ctanoyl derivatives of fatty alcohols by heating them with perfluorooc tanoyl chloride for 15 min at 60 degrees C. Using low-power microwave irradiation (240 W), we can reduce the reaction time to only 2 min. Th e yields of the derivatives were quantitative by both microwave techni que and conventional heating as evidenced by absence of starting mater ial (fatty alcohols) in the HPTLC analysis. The mass spectral fragment ation patterns of the derivatives obtained by microwave irradiation ar e identical to the derivatives prepared by conventional heating. We al so prepared trimethylsilyl derivatives of fatty alcohols, a widely use d derivative, in 1.5 min using microwave irradiation (power 3, 240 W) where the conventional technique requires 20 min. We conclude that mic rowave irradiation can be employed for rapid preparation of perfluoroo ctanoyl and trimethylsilyl derivatives of fatty alcohols for gas chrom atography-mass spectrometric analysis.