## 3 Results  
### Distribution of Fatty Acids in Oils by GC-FID  
Usually the detection and separation of fatty acids from oils is determined by GC-FID, but lately other techniques have been used. The separation, identification, and quantification of the levels of fatty acids in the oils of sunflower, sesame, hep, walnut, linseed, and sea buckthorn were performed through GC-FID analyses. These results were obtained based on the previous analysis of the FAME 37 mixture that was injected and used to obtain the retention time of the fatty acids of interest presented in the oil samples. Figure 1 shows the chromatograms of sunflower, sesame, hep, walnut, linseed, and sea buckthorn oils with peak label. Chromatograms indicate that all the representative peaks of all components were well resolved with a good separation between the peaks in less than 50 min, and this result indicates that the peak overlap was not affected by the peaks of the main constituents. As can be noticed, the major compound in the samples of sunflower, sesame, hep, and walnut oil is linoleic acid (peak label C18: 2n6c). Sesame oil can be differentiated from other oils by its high content of oleic acid (C18: 1n9c), a monounsaturated acid. Sea buckthorn oil in comparison to the types of oil discussed above comprises two major compounds: palmitic acid (peak label C16: 0) and palmitoleic acid (peak label C16: 1). Figure 2a-f show the percentage distribution of fatty acids depending on the degree of saturation and the percentage distribution of fatty acids present in the 6 types of oil samples. Final concentrations of fatty acids were grouped depending on their degree of saturation (saturated, monounsaturated, and polyunsaturated fatty acids) for each oil sample and expressed as minimum, maximum, and average are presented in Table 1.  
Comparing the fatty acid composition of the studied samples, it can be seen that hep oil had the highest content of polyunsaturated acids (74.29%) and the lowest content of monounsaturated acids (14.55%). Sunflower, sesame, hep, walnut, and linseed oils contained a high percent of monounsaturated and polyunsaturated fatty acids, summing approximately 90% of fatty acid composition. Regarding the fatty acid composition of sea buckthorn oil, from Table 1, it can be noticed that this oil had the highest content of saturated fatty acids (41.55%) and a low content of polyunsaturated fatty acids (8.65%), except the sea buckthorn oil sample SB 21, whose concentration was 57.2% in polyunsaturated acids similar to the concentration found in sunflower oil samples. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Saturated**} & \multicolumn{3}{c}{**Monounsaturated**} & \multicolumn{3}{c}{**Polyunsaturated**} \\  & \multicolumn{3}{c}{**Fatty Acids**} & \multicolumn{3}{c}{**Fatty Acids**} & \multicolumn{3}{c}{**Fatty Acids**} \\ \cline{2-10}
**Type of Oil** & \multicolumn{3}{c}{**Concentration (\%)**} & & & & & & \\ \cline{2-10}  & **min.** & **max.** & **Average** & **min.** & **max.** & **Average** & **min.** & **max.** & **Average** \\ \hline Sunflower & 10.29 & 12.71 & 11.20 & 23.58 & 32.17 & 26.10 & 57.31 & 66.13 & 62.71 \\ \hline Sesame & 16.21 & 16.79 & 16.64 & 39.94 & 42.34 & 41.08 & 40.87 & 43.85 & 42.28 \\ \hline Hemp & 10.98 & 11.35 & 11.16 & 13.44 & 15.82 & 14.55 & 72.83 & 75.58 & 74.29 \\ \hline Walnut & 9.91 & 10.33 & 10.08 & 16.90 & 26.16 & 19.70 & 63.93 & 72.97 & 70.22 \\ \hline Linseed & 9.54 & 12.69 & 11.40 & 17.84 & 28.28 & 22.34 & 60.02 & 72.62 & 66.27 \\ \hline Sea buckthorn & 40.61 & 42.5 & 41.55 & 49.58 & 50.00 & 49.79 & 9.39 & 7.92 & 8.65 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Composition of fatty acids (%) grouped by degree of saturation in oil samples. Figure 1: GC-FID chromatogram of oil samples with peak label. Peak label: C14:0—myristic acid; C16:0—palmitic acid; C16:1—palmitoleic acid; C18:0—stearic acid; C18:1n9c —oleic acid; C18:2n6c —linoleic acid; C18:3n3—a-linolenic acid; C20:0 —arachidic acid. Figure 2: _Cont._  
Figure 2: Cont.