Carvacrol (SigmaeAldrich, Belgium), and (E)- cinnamaldehyde (SigmaeAldrich, Belgium) were also dissolved in n-hexane and injected as described for the EOs in order to use the observed retention times to distinguish between carvacrol and thymol, and between (Z)- and (E)- cinnamaldehyde respectively.
For quantification the signal area percentage contribution of each identified compound to the total signal area was used.