This paper describes the design of membrane inlet systems for detection of trace contaminants in environmental samples by Membrane Introduction Mass Spectrometry. A quadropole mass spectrometer equipped with a pervaporation membrane and a jet separator interface was used. The hollow fibre pervaporation membrane was mounted in a cell with transverse flow. Low-level (ppb-ppm) organic compounds (benzene, chloroform, 1,1,1-trichloroethane) in aqueous solutions in the absence or presence of a surfactant could be detected by this technique. The effect of feed flow rate, feed temperature and concentration on membrane performance including flux and enrichment were studied in both binary and multi-component solutions. Fluxes for organic compound increases with flow rate, temperature and feed concentration. Enrichment decreased with temperature. The presence of a surfactant reduced the flux at very high concentrations (Triton X-100; 18 g/l), but the effect was lower than expected. An example is given of industrial feed analysed using this technique.
- Membrane introduction mass spectrometry
- response time
- mass transfer coefficient
- environmental analysis
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