Liquid Chromatography Mass Spectrometry Study of a Eutectic Mixture of bis(2,2‐Dinitropropyl) Acetal/Formal

Abstract

This study is the first attempt to document methodology development undergone using liquid chromatography tandem quadrupole time of flight mass spectrometry (LC-QTOF) to investigate degradation products of eutectic bis(2,2-dinitropropyl) acetal/formal nitroplasticizer (called NP here). Method properties investigated are: desolvation temperature (°C) and spray voltage (V) of the electrospray ionization source, and the development of an acetone system rinse to prevent any residual contamination between sample injections. Details are given on why it is essential to investigate method optimization with changes shown in MS/MS analysis in addition to MS results. Trends in MS/MS analytic results reveal important relationships between baseline and aged materials. In addition to verification of previously proposed fragments, insights offered by this newly developed methodology will also identify new degradation products and shed light on the complexity of NP degradation chemistry.

Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry Analysis of Eutectic Bis(2,2-dinitropropyl) Acetal/Formal Degradation Profile: Nontargeted Identification of Antioxidant Derivatives

“…As a result, NP decomposition proceeds at a faster pace and the accumulation of HNO x , NO x , and water likely dissociates into charged components, which not only create reactive electrophiles (e.g., NO + , NO 2 + NO 3 – , H 2 NO 2 + , and HN 2 O 4 + ) 37 , 38 but also increase the acidity in the aged samples in the later stage of thermal aging. 17 − 22 These conditions can catalyze the nitration reaction of polycyclic aromatic hydrocarbons. 37 , 38 Hence, the fourth and the fifth NO 2 additions are achievable, especially at elevated temperatures and in the presence of HNO 3 ( Figure S18 ).…”

Identification of 2,2‐dinitropropanol, a Hydrolyzed Product of Aged Eutectic Bis(2,2‐dinitropropyl) Acetal – Bis(2,2‐dinitropropyl) Formal Mixture

“…Although a large data set was collected, we present only those LC-QTOF spectra applicable to the verification of the presence of DNPOH in aged samples. Figure 8 Here, we have identified the source of that signal to be DNPOH [18].…”

“…To validate that the presence of DNPOH is not an abnormality in the above presented sample data, Figure 11 plots relevant signal response over the course of the aging study, utilizing an improved method expanded on from our previous work [18]. The air exposed samples are presented as the dry category and the water exposed sample as the wet category.…”

“…Hence, this study uses liquid chromatography tandem quadrupole -time of flight mass spectrometry (LC-QTOF) instrumentation to determine degradation products [4,[16][17][18].…”

“…We have found that condensed phase degradation products have not been identified with a great deal of precision. Hence, this study uses liquid chromatography tandem quadrupole ‐ time of flight mass spectrometry (LC‐QTOF) instrumentation to determine degradation products [4, 16–18].…”