## 3 Results  
### Cattle Nasal Swabs  
Figure 1 shows the comparison of averaged chromatograms of headspace over (\(n=50\) and \(n=50\)) nasal swab samples from'sick' and 'healthy' cattle. The difference (shown in red) illustrates the preliminary separation of disease markers.  
Compounds **1-4** are significantly different (peak areas) between the'sick' and 'healthy' cattle samples (\(p=0.001\), \(p<0.0001\), \(p<0.0001\) and \(p=0.0358\), respectively). It is remarkable to note that statistical differences were obtained considering the complexity of nasal secretions and possible confounding compounds. Table 1 shows a summary of the preliminary ID of compounds, CG column retention time, spectral match and the top five most intense ions. Phenol and \(p\)-cresol were identified also using match with neat standards for these compounds. Since the multidimensional GC-MS has two columns connected in series, it is difficult to use a routine Kovats index system to further improve the quality of preliminary identification. Thus, the top five ions distribution carries the useful spectral information for future comparisons. More research is warranted to confirm these findings.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Compound \#**} & **Preliminary** & **Column** & **Sick Cattle** & **Healthy** & **Confirmed** & **Spectral** & **Top Five Ion** \\  & **ID** & **Retention Time** & **Peak Area** & **Cattle Peak** & **RT with** & **Match (\%)** & **Distribution,** \\  & **(min)** & **(min)** & **(a.u.)** & **Area (a.u.)** & **standard** & **Random (\%)** & **Ion (\%)** \\ \hline \multirow{2}{*}{Compound **1**} & \multirow{2}{*}{Phenol} & \multirow{2}{*}{22.10} & 91,300 & 145,000 & \multirow{2}{*}{yes} & \multirow{2}{*}{62} & 94(100), 65(37), \\  & & & (\(\pm\)44,100) & (\(\pm\)89,700) & & & & 66(633), 39(31), \\ \hline \multirow{2}{*}{Compound **2**} & \multirow{2}{*}{Benzothiazole} & \multirow{2}{*}{22.61} & 120,000 & 378,000 & \multirow{2}{*}{no} & \multirow{2}{*}{78} & 135(100), \\  & & & (\(\pm\)121,000) & (\(\pm\)157,000) & & & & 108(32), 69(17), \\ \hline \multirow{2}{*}{Compound **3**} & \multirow{2}{*}{\(p\)-Cresol} & \multirow{2}{*}{23.3} & 190,000 & 340,000 & \multirow{2}{*}{yes} & \multirow{2}{*}{57} & 108(100), \\  & & & (\(\pm\)128,000) & (\(\pm\)187,000) & & & & 107(89), 77(59), \\ \hline \multirow{2}{*}{Compound **4**} & \multirow{2}{*}{5-Octadecenal} & \multirow{2}{*}{27.80} & 33,100 & 64,100 & \multirow{2}{*}{no} & \multirow{2}{*}{56} & 55(100), 41(46), \\  & & & (\(\pm\)39,900) & (\(\pm\)90,400) & & & & 55(100), 41(97), \\ \hline \hline \end{tabular} Note: values in parantheses are standard deviations.  
\end{table}
Table 1: Preliminary compound identification for markers in nasal swab samples (Figure 1).  
Figure 1: Comparison of averaged ‘sick’ and ‘healthy’ cattle nasal swab samples. The gray is the possible background contributed by the tissues used. The black is the average of all 50 ‘healthy’ cattle samples. The blue is the average of all 50 ‘sick’ cattle samples. The red is the standard deviation between the ‘sick’ and the ‘healthy’ cattle samples (to visualize the presence of probable markers).