Aviv Amirav (1), Raya Seltzer (2), and Abraham Hefetz (3),
1. Professor of Chemistry at Tel Aviv University and Director – Aviv Analytical
2. Graduate student at the department of Zoology at Tel Aviv University
3. Professor of Zoology at Tel Aviv University
- Dominant or highly abundant molecular ions were observed for all the ant compounds, (as shown in Figure 1 and 2) in sharp contrast to standard EI (Figure 2).
- Clear isomer mass spectral effects were observed via isomer related high mass fragments that enabled the elucidation of the isomers structures. These isomer MS effects and the abundant molecular ions proved highly valuable and vastly superior to standard EI in ant wax compounds identification.
- The use of short column ensured that all the wax sample compounds eluted from the column including minor amounts of cholesteryl esters.
- The analysis took only 16 min, which is almost three times faster than with standard GC-MS analysis of such wax compounds although the separation is slightly compromised due to the use of short column.
- The 5975-SMB GC-MS with Cold EI uniquely exhibits uniform response to all the wax compounds thereby as with GC-FID enables quantitative analysis of the wax composition.
- The 5975-SMB GC-MS with Cold EI opens the door for a unique and highly effective isomer distribution analysis characterization of the ant waxes. The 17 ant waxes data could be processed via computer reconstructed single ion monitoring on the molecular ions (RSIM) which enabled clear distinguishing of the various Cataglyphis ants from different places in Israel, even if they were morphologically indistinguishable. Thus, we feel that isomer distribution analysis can serve as a novel tool for ant characterization according to their nest location as demonstrated in Figure 3. Our data strongly supports the hypothesis that isomer distributions play a major role in ant's communication and recognition and that ant communication is based on branched hydrocarbon abundances as a recognition fingerprint.
- We found that the while ants hydrocarbons with even carbon numbers (total carbon numbers) were mostly in the form of branched hydrocarbons, those with odd carbon numbers exhibited much more abundant linear chain hydrocarbons. This finding further illuminates the biochemical synthetic pathways of ants in their formation of epicuticle wax.