Outside the host, viruses will eventually lose their ability to infect cells due to conformational changes that occur to proteins on the viral capsid. In order to undergo a conformational change, these proteins require energy to activate the chemical reaction that leads to the conformational change. In this study, data from the literature is used to calculate the energy required for viral inactivation for a variety of different viruses by means of the Arrhenius equation. We find that some viruses (rhinovirus, poliovirus, human immunodeficiency virus, Alkhumra hemorrhagic fever virus, and hepatitis A virus) have high inactivation energies, indicative of breaking of a chemical double bond. We also find that several viruses (respiratory syncytial virus, poliovirus, and norovirus) have nonlinear Arrhenius plots, suggesting that there is more than a single pathway for inactivation of these viruses.

Sulfonate esters, a class of potentially mutagenic drug impurities, are strictly regulated in pharmaceuticals. On the other hand, sulfite esters and sulfones, analogs of sulfonate esters, have limited safety concerns. However, previously developed analytical methods for sulfonate ester identification cannot be used to differentiate sulfonate esters from the isomeric sulfite esters and sulfones. A tandem mass spectrometric method is introduced here for the differentiation of these compounds. Diisopropoxymethylborane (DIMB) reacts with protonated sulfonate esters, sulfite esters, and sulfones (and many other compounds) in the gas phase to form the product ion [M + H + DIMB – CH3CH­(OH)­CH3]+. Upon collision-activated dissociation (CAD), these product ions generate diagnostic fragment ions that enable the differentiation of sulfonate esters, sulfite esters, and sulfones from each other. For example, SO2 elimination enabled the unambiguous identification of sulfite esters. On the other hand, elimination of CH3BO followed by elimination of (CH3)2CO was only observed for sulfonate esters. Neither type of diagnostic fragment ions was detected for the products of sulfones. However, the product ions formed for sulfones with an additional hydroxyl substituent underwent the elimination of another CH3CH­(OH)­CH3 molecule, which enabled their identification. Finally, ion–molecule reactions of DIMB with various other functionalities were also examined. Some of them yielded the product ions [M + H + DIMB – CH3CH­(OH)­CH3]+ but none of these product ions underwent the diagnostic CAD reactions discussed above. Quantum chemical calculations were employed to explore the mechanisms of the reactions. The limits of detection for the diagnostic ion–molecule reaction product ions in high-performance liquid chromatography (HPLC)/mass spectrometry (MS2) experiments were found to range from 0.075 to 1.25 nmol.

Biomass‐derived degraded lignin and cellulose serve as possible alternatives to fossil fuels for energy and chemical resources. Fast pyrolysis of lignocellulosic biomass generates bio‐oil that needs further refinement. However, as pyrolysis causes massive degradation to lignin and cellulose, this process produces very complex mixtures. The same applies to degradation methods other than fast pyrolysis. The ability to identify the degradation products of lignocellulosic biomass is of great importance to be able to optimize methodologies for the conversion of these mixtures to transportation fuels and valuable chemicals. Studies utilizing tandem mass spectrometry have provided invaluable, molecular‐level information regarding the identities of compounds in degraded biomass. This review focuses on the molecular‐level characterization of fast pyrolysis and other degradation products of lignin and cellulose via tandem mass spectrometry based on collision‐activated dissociation (CAD). Many studies discussed here used model compounds to better understand both the ionization chemistry of the degradation products of lignin and cellulose and their ions' CAD reactions in mass spectrometers to develop methods for the structural characterization of the degradation products of lignocellulosic biomass. Further, model compound studies were also carried out to delineate the mechanisms of the fast pyrolysis reactions of lignocellulosic biomass. The above knowledge was used to assign likely structures to many degradation products of lignocellulosic biomass.