Using design of experiments to optimize derivatization with methyl chloroformate for quantitative analysis of the aqueous phase from hydrothermal liquefaction of biomass

Abstract

Hydrothermal liquefaction is a promising technique for the production of bio-oil. The process produces an oil phase, a gas phase, a solid residue, and an aqueous phase. Gas chromatography coupled with mass spectrometry is used to analyze the complex aqueous phase. Especially small organic acids and nitrogen-containing compounds are of interest. The efficient derivatization reagent methyl chloroformate was used to make analysis of the complex aqueous phase from hydrothermal liquefaction of dried distillers grains with solubles possible. A circumscribed central composite design was used to optimize the responses of both derivatized and nonderivatized analytes, which included small organic acids, pyrazines, phenol, and cyclic ketones. Response surface methodology was used to visualize significant factors and identify optimized derivatization conditions (volumes of methyl chloroformate, NaOH solution, methanol, and pyridine). Twenty-nine analytes of small organic acids, pyrazines, phenol, and cyclic ketones were quantified. An additional three analytes were pseudoquantified with use of standards with similar mass spectra. Calibration curves with high correlation coefficients were obtained, in most cases R (2) > 0.991. Method validation was evaluated with repeatability, and spike recoveries of all 29 analytes were obtained. The 32 analytes were quantified in samples from the commissioning of a continuous flow reactor and in samples from recirculation experiments involving the aqueous phase. The results indicated when the steady-state condition of the flow reactor was obtained and the effects of recirculation. The validated method will be especially useful for investigations of the effect of small organic acids on the hydrothermal liquefaction process.

A concerted systems biology analysis of phenol metabolism in Rhodococcus opacus PD630

“…Overflow metabolites were analyzed using enzyme kits from R-Biopharm (Germany). Phenol and benzoate in the culture supernatant were derivatized using methyl chloroformate (Madsen et al, 2016) and quantified using a custom GC-MS-FID system (gas chromatography-mass spectrometry-flame ionization detector). Briefly, the culture supernatant was centrifuged at 16,000 g for 5 min, and 200 µL of the culture supernatant was mixed with 40 μL of 5.0% (w/w) sodium hydroxide solution, 200 μL of methanol, and 50 μL of pyridine.…”

Assessment of agricultural crops and natural vegetation in Scotland for energy production by anaerobic digestion and hydrothermal liquefaction

“…Total nitrogen (TN) was measured using the Hach Lange TN kits (LCK338). A total of 38 compounds in the water were analysed via GC-MS following derivatization using methyl chloroformate as described previously [7]. The bio-crude and grass samples were analysed for elemental composition using an Elementar CHNS-O Vario Macrocube elemental analyser.…”

Techno‐economic analysis of a novel hydrothermal liquefaction implementation with electrofuels for high carbon efficiency

“…The evaporators are modeled by a two‐outlet flash (Flash2) component. The input aqueous phase for the MEE was modeled by 16 compounds mixed with water from the Aspen Plus ® library based on experimental data from Madsen et al . The final product contains 16 chemical compounds with a 20% water content.…”