A review on the electron ionisation and fast atom bombardment mass spectrometry of polyphenols naturally occurring in olive wastes and some of their synthetic derivatives

Electron ionization and fast atom bombardment mass spectrometry (EI- and FA B-MS) are the spectroscopic methods most extensively used for analysing the main polyphenols naturally occurring in olive oil mill waste waters (omww) and in dropped olive leaves. EI-MS is very suitable for analysing catechol , 4-methylcatechol, tyrosol and hydroxytyrosol, the main polyphenols identi fied in omww, The EI method has also proved to be suitable for analysing th eir acetyl derivatives, but does not allow the molecular ion of diacetyltyr osol and its isomers to be detected. FAB-MS is the only adequate ionization method for detecting the molecular ion of diacetyltyrosol and is more suit able than EI-MS for analysing triacetylhydroxytyrosol. The mechanisms of fr agmentation of the acetyl derivatives of tyrosol and hydroxytyrosol were de termined using the EI and FAB ionization methods. In addition, FAB-MS, whic h was performed in both positive and negative ion modes, was shown to be th e only adequate ionization method for analysing oleuropein, a phenol glucos ide which occurs naturally in olive leaves. The positive ion FAB-MS was sho wn to be much more suitable than EI-MS for analysing the aglycone obtained following the hydrolysis of oleuropein by beta-glucosidase. These results c onfirmed the versatility of FAB-MS for analysing low molecular weight compo unds, for which EI-MS proved to be an unsatisfactory method. Copyright (C) 1999 John Wiley & Sons, Ltd.