Use of proton transfer reaction time-of-flight mass spectrometry for quantitative monitoring of toxic nitramines in the environment

Abstract:

Naturally occurring aliphatic amines and industrially emitted aromatic amines and alkanolamines produce toxic nitramines, (R₁R₂)-N-NO₂, when photo-oxidized in the atmosphere in the presence of nitrogen oxides (NO_x). Particular concerns arise from amine-based CO₂ capture where the amine solution may get nitrated by NOx in the flue gas. An on-line analytical technique for measuring nitramines in industrial emissions and in ambient air is thus in high demand.

Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) is a state-of-the-art technique for on-line measurements of volatile organic compounds (VOCs) in air. Herein, we report on the use of high mass resolution proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) for on-line analysis of nitramines. We generated a mass spectral library from a series of nitramines and investigated the analytical performance of PTR-ToF-MS in terms of sensitivity, precision, accuracy and detection limit. We will discuss limitations of the innovative technique and propose measurement strategies for future emission and ambient measurements.