Biomass includes substances of organic origin and is one of the most complex systems from which renewable energy can be obtained. Biomass conversion methods used to generate energy include pyrolysis, gasification, liquefaction, and direct combustion. Increasing the use of biomass as an energy source solves the problems of environmental pollution with harmful gases, and thus preserves human health. Pyrolysis is a process of thermochemical decomposition that takes place without the presence of oxygen. Products that can be obtained by pyrolysis can generally be divided into solid residue (carbon, ash), gases (CO, CO2, CH4, H2 and other light hydrocarbons) and vapors or liquids (aromatics, water, tar, etc.). Pyrolytic oil is a liquid product formed by pyrolysis of biomass. The properties of the obtained bio-oils mostly depend on the type of selected biomass and working conditions, and it is especially emphasized by the increased density, separation of production and ease of transport and use, which is why they are widely used in commercial use. For this purpose, analytic methods such as gas chromatography with mass spectrometry, spectrometry of nuclear magnetic resonance, Fourier infrared spectroscopy and thermogravimetric analysis can be utilized. The analysis of pyrolytic oils presents several challenges and limitations that can be attributed to the presence of reactive chemical species and other high molecular weight molecules obtained by the pyrolytic route.