Study of calcium soap pyrolysates derived from Macauba fruit ( Acrocomia sclerocarpa M.). Derivatization and analysis by GC/MS and CI-MS

Abstract

An investigation has been undertaken of pyrolysates obtained from calcium soaps prepared from vegetable oils in Macauba fruit ( Acrocomia sclerocarpa M.). GC/MS showed the samples to be very complex, exhibiting more than 40 compounds. To attempt to separate and identify the constituents different techniques were used: methoximation, EI and ammonia CI-MS. n-Alkane and 1-alkane series were located and identified by the characteristic ions m/ z 85 and 83 respectively, and the molecular ions in the case of the lower members of the series. Identification of homologous series was further confirmed by a mass spectral search (NIST), visual comparison with published mass spectra and use of linear retention index data. To target the ketones and aldehydes, methoxime derivatization was employed. With EI-MS the methoximes gave a specific ion at m/ z 87, but no molecular ion. Ammonia CI-MS was used to confirm the molecular weight of both underivatized ketones and methoximes in correlation with the retention data.