Lignocellulosic biomass, in particular wood, is a complex mixture containing cellulose, hemicellulose, lignin, and other trace compounds. Chemical analysis of these biomasses, especially lignin components, is a challenge. Lignin is a highly reticulated polymer that is poorly soluble and usually requires chemical, enzymatic, or thermal degradation for its analysis. Here, we studied the thermal degradation of lignocellulosic biomass using a direct insertion probe (DIP). The DIP was used with two ionization sources: atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) coupled to ultrahigh-resolution mass spectrometry. Beech lignocellulosic biomass samples were used to develop the DIP-APCI/APPI methodology. Two other wood species (maple and oak) were analyzed after optimization of DIP parameters. The two ionization sources were compared at first and showed different responses toward beech samples, according to the source specificity. APPI was more specific to lignin degradation compounds, whereas APCI covered a larger variety of oxygenated compounds, e.g., fatty acids and polyphenolics compounds, in addition to lignin degradation products. The study of the thermodesorption profile gave information on the different steps of lignocellulosic biomass pyrolysis. The comparison of the three feed sample types (oak, maple, and beech), using principal component analysis (PCA) with DIP-APCI experiments, showed molecular level differences between beech wood pellets and the two other wood species (maple and oak).

No abstract

Bitumen is a highly complex matrix, generally obtained as vacuum residues of the crude oil distillation. This material is majorly used as binder for the construction of asphalt pavement. Mechanical properties of bitumen are greatly influenced by its composition, including heteroatom-containing compounds, and by the use of additive cocktails. Polymer-modified bitumen (PMB) can be produced by the use of additives such as styrene–butadiene–styrene copolymer (SBS) to avoid asphalt stiffness and pavement cracking. To characterize a complex mixture such as bitumen at the molecular level, instruments such as Fourier transform ion cyclotron resonance are required. However, the size of SBS, which is typically >150 kDa, is far above the mass range of Fourier transform ion cyclotron resonance (FTICR) instruments. Direct insertion probe atmospheric pressure chemical ionization (DIP-APCI) can be used to pyrolyze SBS and observe its fragments within a PMB sample in a lower mass range. This technique does not require any sample preparation because the sample is analyzed in pure form and is also adapted to characterize heavy petroleum products with its ability to ionize a large range of molecules including nonpolar, polar, and aromatic species. DIP-APCI-FTICR was used with fixed and ramped temperature for the analysis of base bitumen, SBS, and PMB samples. It allowed for the characterization of the thermodesorption products of bitumen and the pyrolysis products of SBS. The main markers of SBS appear to be multimeric butadiene ions. This SBS ion series is clearly evidenced in PMB using DBE vs C# and modified Kendrick mass defect plots. Overall, this study presented a fast DIP-APCI-FTICR characterization of bitumen and PMB without any sample preparation.

No abstract

No abstract

No abstract

Gasoline emissions contain high levels of pollutants, including particulate matter (PM), which are associated with several health outcomes. Moreover, due to the depletion of fossil fuels, biofuels represent an attractive alternative, particularly second-generation biofuels (B2G) derived from lignocellulosic biomass. Unfortunately, compared to the abundant literature on diesel and gasoline emissions, relatively few studies are devoted to alternative fuels and their health effects. This study aimed to compare the adverse effects of gasoline and B2G emissions on human bronchial epithelial cells. We characterized the emissions generated by propane combustion (CAST1), gasoline Surrogate, and B2G consisting of Surrogate blended with anisole (10%) (S+10A) or ethanol (10%) (S+10E). To study the cellular effects, BEAS-2B cells were cultured at air-liquid interface for seven days and exposed to different emissions. Cell viability, oxidative stress, inflammation, and xenobiotic metabolism were measured. mRNA expression analysis was significantly modified by the Surrogate S+10A and S+10E emissions, especially CYP1A1 and CYP1B1. Inflammation markers, IL-6 and IL-8, were mainly downregulated doubtless due to the PAHs content on PM. Overall, these results demonstrated that ultrafine particles generated from biofuels Surrogates had a toxic effect at least similar to that observed with a gasoline substitute (Surrogate), involving probably different toxicity pathways.