2.2 Chemical characterization Chemical analysis of EO was performed by gas chroma-tography-mass spectrometryGC-MSin a Shimadzu device, model QP5050A, using a capillary column, CBP-5, 50 m in length, with an internal diameter of 0.25 mm and 0.25 μm film thickness. The carrier gas was He and the identification of EO compounds was made on the basis of the National Institute of Standards and TechnologyNISTlibrary, analysis of the mass spectra, and also data in the literature17.