Some aspects of isobutane and ammonia chemical ionization for the analysis of volatile esters and phenylpropanoids occurring in essential oils

The fragmentation reactions of some terpenoid esters and pbenylpropanoids under the conditions of isobutane and ammonia chemical ionization (CI) arc discussed. The esters show different behaviour with these two gases with respect to determination of the relative molecular mass and information about the structure of the molecules. The structural isomers of the phenylpropanoids can unequivocally be distinguished with both isobutane and ammonia CI. Cis/trans isomers of the phenylpropanoids show virtually identical CI spectra.