Chemical composition of bio-oil obtained via hydrothermal liquefaction of Arthrospira platensis biomass

The chemical composition of bio-oil obtained from Arthrospira platensis biomass via hydrothermal liquefaction at $240$–$330^{\circ}$C has been studied with an elemental analysis and Fourier transform ultrahigh resolution mass spectrometry with ionic cyclotron resonance. An increase in temperature leads to an increased bio-oil yield, decreased oxygen, and an increase in the amount of carbon and nitrogen. The weighted Kendrick mass defect histogram showed for the first time that the main nitrogen-containing and oxygen-containing compounds are $\rm ON{,}\,\rm O_2\rm N_3{,}\,\rm O_3\rm N_2{,}\,\rm ON_2{,}\,\rm N$, and $\rm N_2$. The character of the change in their relative amount in bio-oil with a temperature change is also revealed. The Venn diagram shows the intersection of the sets of molecular formulas found in bio-oil samples obtained at different temperatures. The results may be used to optimize the hydrothermal liquefaction of microalgae and their subsequent processing into motor fuel.