Direct detection and identification of volatile organic compounds dissolved in organic solvents by reversed-phase membrane introduction tandem mass spectrometry

Abstract

A new technique Is described for the direct detection and Identification of volatile organic compounds dissolved In organic solvents. The method uses a porous membrane Introduction system to a mass spectrometer and Is capable of continuous on-line monitoring. The porous polypropylene membrane chosen for this work allows sufficient amounts of the solvent to penetrate Into the Ion source for chemical Ionization (Cl) to occur with the vaporized solvent acting as the reagent gas. Solute molecules permeate the membrane together with the solvent and can be analyzed by CI/MS and tandem mass spectrometry (MS/MS). In cases In which the solute can not be chemically Ionized by the vaporized solvent Cl-plasma, It Is possible to co-lntroduce a conventional Cl reagent gas to achieve additional control of the Ionization process. With this technique, a broad range of compounds dissolved In organic solvents can be detected In the sub-ppm range with rise and fall times faster than 10 s. Detection limits depend on the efficiency of Ionization, not on the rate of passage through the membrane, and they can often be Improved by using tandem rather than single-stage mass spectrometry. As an example of the application of the technique, the detection and Identification of additives In gasoline samples Is demonstrated.

Real-Time Broad Spectrum Characterization of Waste by Membrane Introduction Mass Spectrometry

“…Microporous membranes do not reject the solvent and so they do not enrich the permeate in the analyte as do silicone and other amorphous membranes. They are, however, more suitable for larger and more polar compounds, and they may also have considerable advantages in terms of rapid response times and freedom from memory effects [12]. We will also investigate on-line extraction methods for SVOCs in soil.…”

Advances in Membrane Inlet Mass Spectrometry (Mims)

“…The extra product ions at m/z 39 and 63 in the spectrum obtained from the gasoline sample are derived from toluene, a major constituent of gasoline. Adapted from reference [40] 260 Brought to you by | Purdue University Libraries Authenticated Download Date | 5/27/15 8:03 PM…”

In situ determination of porewater gases by underwater flow‐through membrane inlet mass spectrometry

“…Membrane inlet mass spectrometry (MIMS) has proven to be a reliable and multifaceted tool for analysis of dissolved gases in a wide variety of media, including sediment porewater Hansen and Degn 1996;Johnson et al 2000;Lauritsen et al 1992;Smith et al 2008). Previous MIMS analysis of sediment porewater involved direct insertion of membrane probes into sediment cores ex situ (e.g., Lloyd et al 1986).…”