Figure 2. GC-MS TIC traces of the Dufour gland extracts of Crematogaster striatula by electronic impact ionization (EI): injection of 1 µL of hexanic extract.

The major double peak at a retention time of 26.15 minutes, for example, corresponds to two isomers of compound C21H30O3 (m/z 330). The trace shows other double or single peaks corresponding to C16 at C23 compounds.