A Field-Portable Membrane Introduction Mass Spectrometer for Real-time Quantitation and Spatial Mapping of Atmospheric and Aqueous Contaminants

Abstract

4Statoil Petroleum ASA, TPD RDI Frontier Developments, Trondheim, Norway MIMSAbstract. Environmental concentrations of volatile and semivolatile organic compounds (VOC/SVOCs) can vary dramatically in time and space under the influence of environmental conditions. In an industrial setting, multiple point and diffuse sources can contribute to fugitive emissions. Assessments and monitoring programs using periodic grab sampling provide limited information, often with delay times of days or weeks. We report the development and use of a novel, portable membrane introduction mass spectrometry (MIMS) system capable of resolving and quantifying VOC and SVOCs with high spatial and temporal resolution, in the field, in real-time. An electron impact ionization cylindrical ion trap mass spectrometer modified with a capillary hollow fiber polydimethylsiloxane membrane interface was used for continuous air and water sampling. Tandem mass spectrometry and selected ion monitoring scans performed in series allowed for the quantitation of target analytes, and full scan mode was used to survey for unexpected analytes. Predeployment and in-field external calibrations were combined with a continuously infused internal standard to enable real-time quantitation and monitor instrument performance. The system was operated in a moving vehicle with internet-linked data processing and storage. Software development to integrate MIMS and relevant metadata for visualization and geospatial presentation in Google Earth is presented. Continuous quantitation enables the capture of transient events that may be missed or under-represented by traditional grab sampling strategies. Real-time geospatial maps of chemical concentration enable adaptive sampling and in-field decision support. Sample datasets presented in this work were collected in Northern Alberta in 2010-2012.

Condensed Phase Membrane Introduction Mass Spectrometry with Direct Electron Ionization: On-line Measurement of PAHs in Complex Aqueous Samples

“…Potentially, these approaches can provide rapid analytical results, reducing time delays and possible contamination/losses from sample work-up and off-line measurement by conventional methods (e.g., GC or LC-MS). One of these on-line approaches, membrane introduction mass spectrometry (MIMS) [2,3], uses a semipermeable membrane interface to transfer analytes from complex samples (gaseous, aqueous, or slurry) to a mass spectrometer for their measurement, and we have demonstrated that it is well suited to the incorporation in portable MS systems [4]. With MIMS, analytes are directly transferred from the sample as a mixture based on their individual permselectivity in the membrane material, with no chromatographic separation.…”

“…Modifications included reducing the diameter and complexity of the solvent inlet lines, replacing them with a 0. 4 Figure 1. Schematic of experimental apparatus Canada) that directly connected the CP-MIMS probe to the inlet port of one pump head.…”

Mini 2000: A Robust Miniature Mass Spectrometer with Continuous Atmospheric Pressure Interface

“…Up until now, different kinds of miniature mass spectrometers have been developed, mainly using an ion trap as the mass analyzer, which is connected with different atmospheric pressure interfaces (APIs), including the membrane inlet (MI) [14][15][16][17], discontinuous atmospheric pressure interface (DAPI) [10,18,19], and continuous atmospheric pressure interface (CAPI) [20,21]. Among these APIs, MI was the first one to be adopted in MS systems.…”

Discrimination of constructed air samples using multivariate analysis of full scan membrane introduction mass spectrometry (MIMS) data

“…Full scan MIMS data contains the overlapping mass spectra of all permeating molecules. Targeted quantitative analysis can be achieved through the use of tandem mass spectrometry and/or selected ion monitoring in conjunction with the use of a continuously infused, isotopically labelled internal standard . MIMS is well suited to mobile deployment, and during field campaigns we have observed differences in the full scan MIMS data from distinct contamination sources .…”

“…Targeted quantitative analysis can be achieved through the use of tandem mass spectrometry and/or selected ion monitoring in conjunction with the use of a continuously infused, isotopically labelled internal standard . MIMS is well suited to mobile deployment, and during field campaigns we have observed differences in the full scan MIMS data from distinct contamination sources . We have proposed that full scan MIMS data can be used to 'fingerprint' ambient air samples and, in combination with chemometric techniques, be used to identify, and apportion, sources of contamination …”