1.2. Extraction time
Three extraction times (2, 4 and 6 h) were investigated in this section. The recovery of volatile components increased with the longer extraction time but 4 h was chosen as the optimum time. This was because low volatility components were hardly observed with 6 h extraction and high volatility at 2 h. Referring to Fig. 4, the number of volatile components peaks collected at both specific times was generally the same. Similarly to the abundance of the each peak, there was only a small difference between the two chromatograms.
In this section, the abundances of intermediate volatility and low volatility were expected to increase with longer extraction time. Although it does not obviously appear on the chromatogram, this hypothesis agreed with the results. The early peaks on the chromatogram were high in abundance when sample was