SCOPE AND LIMITATIONS OF FLASH PYROLYSIS-GAS CHROMATOGRAPHY MASS-SPECTROMETRY AS REVEALED BY THE THERMAL-BEHAVIOR OF HIGH-MOLECULAR-WEIGHT LIPIDS DERIVED FROM THE GREEN MICROALGA BOTRYOCOCCUS-BRAUNII

Curie point pyrolysis-gas chromatography/mass spectrometry studies of four types of high-molecular-weight (HMW) lipids isolated from the gre en microalga Botryococcus braunii race A were performed to determine t he thermal behaviour of these lipids and to propose mechanisms of pyro lysis for these types of compounds. Although two types of lipids induc ed detectable pyrolysis products upon heating of the ferromagnetic wir es at Curie temperatures of 610 and 770-degrees-C, transfer problems f rom the pyrolysis unit to the GC column were observed. Therefore, furt her analysis of the pyrolysis residues is suggested. Furthermore, two types of lipids presenting long alkyl chains (up to C64) did not pyrol yse under the experimental conditions but were thermally extracted fro m the wire at any of the tested temperatures. Some of these HMW lipids could, however, be analysed by high-temperature gas chromatography (t emperatures up to 375-degrees-C). Mechanisms of pyrolysis, partly base d on previous studies, were proposed for the two types of ether lipids . These mechanisms allowed the structural reconstruction of the main b iopolymer that composes the cell outer walls of the microalga B. braun ii race L. This biomacromolecule was found to be comprised of C40 isop renoid (lycopene) units, ether linked at the C(14) and C(15) positions .