Tracking Monochloramine Decomposition in MIMS Analysis

Abstract

Membrane-introduction mass spectrometry (MIMS) has been presented as one of the promising approaches for online and real-time analysis of monochloramine (NH2Cl) in diverse matrices such as air, human breath, and aqueous matrices. Selective pervaporation of NH2Cl through the introduction membrane overcomes the need for sample preparation steps. However, both the selectivity and sensitivity of MIMS can be affected by isobaric interferences, as reported by several researchers. High-resolution mass spectrometry helps to overcome those interferences. Recent miniaturization of Fourier transform—ion cyclotron resonance—mass spectrometry (FT-ICR MS) technology coupled to the membrane-introduction system provides a potent tool for in field analysis of monochloramine in environmental matrices. Monochloramine analysis by MIMS based FT-ICR MS system demonstrated decomposition into ammonia. To further clarify the origin of this decomposition, headspace analyses after bypassing the membrane were undertaken and showed that monochloramine decomposition was not exclusively related to interactions within the membrane. Adsorption inside the MIMS device, followed by surface-catalyzed decomposition, was suggested as a plausible additional mechanism of monochloramine decomposition to ammonia.

Analysis of VOCs in Liquids through Vaporization in a Tubular Oven Monitored by Chemical Ionization Mass Spectrometry

“…The number of papers reporting applications of PTR-MS for the detection of VOCs in liquids is much more limited than in gases. The use of Membrane Inlet Mass Spectrometry (MIMS) associated with a PTR-FT-ICR has been described by Louarn et al [ 27 , 28 ] and Roumiguières et al [ 29 ]. In this method, the hydrophobic membrane acts both as a physical barrier between the sample solution and the mass spectrometer and as a VOC concentrator.…”

Is It Possible to Measure Monobromamine Using Colorimetric Methods Based on the Berthelot Reaction, Like for Monochloramine?

“…A literature review reported the use of five types of approach to determine TRO: colorimetric, titrimetric, potentiometric or amperometric analysis, and chromatography or membrane-introduction mass spectrometry (MIMS) [22,23]. The colorimetric approach has shown great potential, due to its simplicity, possible miniaturization, and application for real-time and on-site analysis.…”