## 3 Results
### Gas Chromatography-Mass Spectrometry of Bio-Oil  
The results of the GC-MS of bio-oil are presented in Table 5. During the analysis in this work, 19 compounds were identified: phenol and its alkyl derivatives, indole and its alkyl derivatives, palmitic acid, hexadecanamide and its alkyl derivatives, and oleic acid diethanolamide. A total of 63% of the peaks of the detected compounds were identified. Similar compounds were obtained in other works [30; 43; 65]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Element** & **Content, \(\mathbf{\mu_{g}\times g^{-1}}\)** & **Element** & **Content, \(\mathbf{\mu_{g}\times g^{-1}}\)** & **Element** & **Content, \(\mathbf{\mu_{g}\times g^{-1}}\)** \\ \hline Na & 611 \(\pm\) 65 & Rb & 0.07 \(\pm\) 0.01 & Ce & 0.047 \(\pm\) 0.002 \\ Mg & 174 \(\pm\) 16 & Cd & 0.28 \(\pm\) 0.02 & Pr & 0.004 \(\pm\) 0.001 \\ Al & 68 \(\pm\) 10 & Te & \textless{}0.01 & Nd & 0.013 \(\pm\) 0.003 \\ K & 390 \(\pm\) 75 & Cs & 0.0025 \(\pm\) 0.0005 & Sm & 0.0025 \(\pm\) 0.0009 \\ Cr & 4.7 \(\pm\) 0.9 & Re & \textless{}0.0004 & Eu & 0.0006 \(\pm\) 0.0001 \\ Mn & 5.1 \(\pm\) 0.3 & Tl & \textless{}0.03 & Gd & 0.0024 \(\pm\) 0.0007 \\ Fe & 1135 \(\pm\) 29 & Pb & 0.93 \(\pm\) 0.08 & Tb & 0.0004 \(\pm\) 0.0001 \\ Ni & 40 \(\pm\) 4 & Bi & 0.009 \(\pm\) 0.002 & Dy & 0.0019 \(\pm\) 0.0003 \\ Cu & 45 \(\pm\) 2 & Th & 0.0029 \(\pm\) 0.0007 & Ho & 0.00040 \(\pm\) 0.00005 \\ Zn & 113 \(\pm\) 4 & U & 0.006 \(\pm\) 0.001 & Er & 0.0015 \(\pm\) 0.0002 \\ Ga & 1.17 \(\pm\) 0.02 & Ru & \textless{}0.001 & Tm & \textless{}0.0001 \\ Sr & 1.5 \(\pm\) 0.3 & Rh & \textless{}0.0004 & Yb & 0.0011 \(\pm\) 0.0002 \\ Ba & 2.0 \(\pm\) 0.4 & Pd & \textless{}0.002 & Lu & \textless{}0.0002 \\ Li & 0.05 \(\pm\) 0.01 & Ir & \textless{}0.002 & & \\ Be & \textless{}0.008 & Pt & \textless{}0.001 & & \\ V & 0.21 \(\pm\) 0.02 & Sc & 0.006 \(\pm\) 0.001 & & \\ Co & 0.91 \(\pm\) 0.02 & Y & 0.014 \(\pm\) 0.003 & & \\ As & 0.17 \(\pm\) 0.02 & In & 0.0015 \(\pm\) 0.0005 & & \\ Se & \textless{}0.07 & La & 0.027 \(\pm\) 0.004 & total: & 2593 \(\pm\) 207 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The results of determining the content of elements in bio-oil that was obtained by the HTL method from microalgae _Arthrospira platensis_ after 15 days of cultivation in an atmospheric gas chamber at an initial CO\({}_{2}\) concentration of 8 vol.%. \begin{table}
\begin{tabular}{c c c} \hline \hline
**No. Peak** & **Retention Time, min** & **Name of the Chemical** \\  & **Compound** & **Peak Area,\%** \\ \hline
1 & 5.915 & phenol & 1.08 \\
2 & 7.335 & p-cresol & 0.60 \\
3 & 8.699 & 4-ethylphenol & 1.57 \\
4 & 9.238 & benzene & 0.44 \\
5 & 10.547 & indole & 0.37 \\
6 & 10.764 & 2H-inden-2-one, 1.4,5,6,7,7a- & 0.52 \\  & & hexadro-7a-methyl-,(S)- & \\
7 & 11.419 & 1,2,3,4-thethahydro-1,6,8- & \\  & trimethylnaphthalene & 1.02 \\
8 & 11.783 & 3-metinlinde & 1.35 \\
9 & 15.429 & heptodecane & 8.31 \\
10 & 18.218 & palmitic acid & 13.35 \\
11 & 18.345 & 5H-period[4,3-b]indole & 1.38 \\
12 & 18.409 & 5H-period[4,3-b]indole & 0.73 \\
13 & 20.151 & palmitic acid amide & 2.87 \\
14 & 20.456 & N-metilgeksadeakanamid & 3.46 \\
15 & 20.813 & N-etilgeksadeakanamid & 3.24 \\
16 & 21.578 & N-propilgeksadeakanamid & 0.63 \\
17 & 21.976 & N-bultigeksadeakanamid & 5.95 \\
18 & 22.829 & N-pentigelgesadeakanamid & 12.97 \\
19 & 24.188 & oleic acid diethanolamide & 2.98 \\  & total: & 62.82 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The results of relative quantification of the content of the identified compounds in bio-oil by GC-MS. In microalgae bio-oil, six main types of chemical compounds can be distinguished according to their functional groups: monoaromatic compounds and their derivatives, aliphatic compounds, fatty acids, nitrogenous compounds, polyaromatic compounds and other oxygenated compounds such as alcohols, aldehydes and ketones [43]. In the current work, we obtained microalgae with a high carbohydrate content, significant protein content and low lipid content.