MICROWAVE-INDUCED RAPID SYNTHESIS OF 4-CARBETHOXYHEXAFLUOROBUTYRYL DERIVATIVES OF FATTY ALCOHOLS - A NOVEL DERIVATIVE FOR GAS-CHROMATOGRAPHY CHEMICAL-IONIZATION MASS-SPECTROMETRIC STUDY

Structural analyses of fatty alcohols are usually performed as acetate , trifluoroacetate or trimethylsilyl derivatives which produce charact eristic molecular ions at m/z < 400. We describe a new derivatization technique of fatty alcohol using 4-carbethoxyhexafluorobutyryl chlorid e. The derivatization reaction requires either 30 min of incubation of the reaction mixture at 60 degrees C, or 4 min of microwave irradiati on using 240 W power. The yields of the derivatives were quantitative under both heating condition and microwave irradiation. The 4-carbetho xy hexafluorobutyryl derivatives of fatty alcohols produce characteris tic protonated molecular ion peaks in the range of m/z 493 (cetyl alco hol) to m/z 549 (arachidyl alcohol) in the chemical ionization mode us ing methane as reagent gas. The molecular ion peaks were 54 u more tha n the conventional heptafluorobutyryl derivatives of fatty alcohols wh ich can also be prepared by microwave irradiation in 3 min (240 W). Th e new derivatives are less volatile than the conventional heptafluorob utyryl derivatives.