Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry

Abstract

Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry is a powerful tool for identifying and quantifying chemical components in complex mixtures. It is often used to analyze gasoline, jet fuel, diesel, bio-diesel and the organic fraction of bio-crude/bio-oil. In most of those analyses, the first dimension of separation is non-polar, followed by a polar separation. The aqueous fractions of bio-crude and other aqueous samples from biofuels production have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fractions obtained from the hydrothermal liquefaction of algae were characterized by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation in the second. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column configuration. Results from qualitative characterization of the aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry are highlighted.

Quantitative Characterization of Aqueous Byproducts from Hydrothermal Liquefaction of Municipal Wastes, Food Industry Wastes, and Biomass Grown on Waste

“…All aqueous byproducts from HTL of wastes were characterized using a LECO (St. Joseph, MI) Pegasus 4D instrument. The data acquisition method has been described extensively in the literature. , For each sample, 0.5 μL was injected into the gas chromatograph. The GC injector temperature was maintained at 260 °C.…”

“…The data acquisition method has been described extensively in the literature. 33,45 For each sample, 0.5 μL was injected into the gas chromatograph. The GC injector temperature was maintained at 260 °C.…”

Quantitative characterization of the aqueous fraction from hydrothermal liquefaction of algae

“…Chemical compounds were identified using the NIST2008 mass spectral database. This method was described in detail in the literature [27]. In addition to identification, the GC × GC -TOF-MS was also used to quantify N-methyl succinimide and 3-pyrindol utilizing the nitrogen standard and procedure described under the "Gas chromatography analysis" section.…”

Quantitative analysis of the aqueous fraction from the Fe-assisted hydrothermal liquefaction of oil palm empty fruit bunches

“…Fast pyrolysis and hydrothermal liquefaction reactions have been extensively studied as methods for the liquefaction of biomass resources and their subsequent use as fuels and chemical feedstocks [1,2]. The hydrothermal liquefaction reaction is a promising method for the liquefaction of biomass, and operates at moderate temperatures (280-370 °C) and high pressures (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) [3][4][5][6].…”

“…Reports on the analysis of the aqueous fractions from the hydrothermal liquefaction of biomass have been published; however, quantitative analyses are limited to only a few cases [15][16][17][18][19]. As analytical methods, gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID) are often used; these methods are powerful because they can rapidly analyze multicomponent mixtures.…”