Development of membrane introduction mass spectrometry for monitoring trace organics in water

This paper describes the design of membrane inlet systems for detection of trace contaminants in environmental samples by Membrane Introduction Mass S pectrometry. A quadropole mass spectrometer equipped with a pervaporation m embrane and a jet separator interface was used. The hollow fibre pervaporat ion 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 concentr ation on membrane performance including flux and enrichment were studied in both binary and multi-component solutions. Fluxes for organic compound inc reases with flow rate, temperature and feed concentration. Enrichment decre ased with temperature. The presence of a surfactant reduced the flux at ver y 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 techn ique.