## 3 Results and Discussions
### Chromatographic Considerations and Sample Analysis
Although strong GC\(\times\)GC-TOFMS signals were not obtained for these samples, further analytical optimization may prove valuable in the future for their characterization. Figure 2 shows the fresh resin and beeswax mix characterized on the three different column sets. Each column set yielded a slightly different structure of chromatogram. The first column set (top) is a non-polar \(\times\) polar column combination, which is a conventional column set used for initial testing. The middle chromatogram demonstrates a mid-polar \(\times\) polar column combination, and the bottom chromatogram demonstrates a polar \(\times\) mid-polar combination. The groupings of terpen and terpen appear at different angles depending on the column set. The best separation was obtained by the Rtx-624 Sil MS \(\times\) Stabilwax column set in this study. However it is suspected that optimization of conditions could potentially lead to sufficient separation over the chromatographic space using any one of these phase combinations. Using the first column set, there was a large amount of peak tailing in both the \({}^{1}\)D and \({}^{2}\)D. This phenomenon was attributed to the thinner films used for the columns in the Rtx-5 MS \(\times\) Rtx-17 Sil MS set in comparison to the other column sets tested. Second dimension tailing was apparent for many of the samples, as seen in Figure 1. However, some samples also exhibited peak tailing in the \({}^{1}\)D which led to exaggerated \"L\"-shaped peaks. This was most apparent for samples that contained carboxylic acids, such as the hide sample displayed in Figure 3. Increasing the film thickness of the columns increased the retention time of specific compounds, yet allowed for improved resolution of the volatile compounds being analyzed. The third column combination, Stabilwax \(\times\) Rtx-200 Sil MS, had reduced peak tailing in the \({}^{1}\)D due to the thicker film on this column, but continued to exhibit considerable peak tailing in the \({}^{2}\)D due to the thin film on the Rtx-200 Sil MS column. On the first column set with thin film thicknesses in both dimensions, some compounds tailed across the majority of the \({}^{2}\)D, which is not ideal in a GC\(\times\)GC analysis where the \({}^{2}\)D should be used as an additional dimension of selectivity. Nonetheless, due to the preliminary nature of this work, this column set was used for initial analysis of all samples as it was considered to be the conventional column set and would, therefore, provide a potential starting point for comparison to the literature. However, future analyses will likely be performed using the Rxi-624 Sil MS \(\times\) Stabilwax column set due to the improved peak shape and resolution for the type of compounds being analyzed. Figure 3 also demonstrates the complexity of the volatile signature of these samples. The red insert displays the dynamic range of compounds and potential for co-elution in the first dimension. These issues are mitigated using GC\(\times\)GC whereby the selectivity of the secondary phase affords improved peak capacity for separating trace compounds from high abundance compounds. Selected compounds labelled in Figure 3 demonstrates the wide range of potential compounds that can be encountered when examining volatiles from mammalian tissues. The ability to fully characterize the complexity of these types of matrices, even in trace quantities, will be extremely beneficial to improve the characterization of volatiles from archaeological residues.