Membrane introduction mass spectrometry methods

Liquid membrane enrichment coupled to mass spectrometry. Membrane introduction mass spectrometry (MIMS) is an established method of sample... 

In an attempt to overcome the significant difficulties that the presence of water vapor poses to the analysis of very volatile compounds, purge-and-membrane extraction techniques have been developed that largely prevent the introduction of water into the analytical system. Typical implementations of this form of sample introduction have been called by its developers membrane extraction with a sorbent interface (MESI),97 or membrane introduction mass spectrometry (MIMS).98 " They are based on a silicone hollow-fiber membrane that is inserted into the sample to be monitored, and the passing of a certain volume of inert gas through the membrane. Volatile compounds permeate the membrane and are swept to the adsorbent trap from which they are desorbed into the GC. This method of sample introduction is particularly suited for field and process monitoring and for dirty samples, since it prevents any nonvolatile compounds from entering the analytical system.100... 

The need for maximum sample throughput and minimal human interaction within analytical procedures has provided considerable impetus to the development of integrated systems. SPE-LC in-tube SPME followed by ultraviolet (UV) or MS detection and membrane introduction mass spectrometry (MIMS) have both been used to this end. Submersible MIMS systems capable of extended underwater deployment down to 200 m and with a mass range of up to 200 amu have recently come onto the market. Elow injection coupled with MIMS allows fast, near-real-time determination of, for example, phenols in water. Derivatization of the phenols with acetic anhydride can be used to enhance both the selectivity and sensitivity of this method. Other online derivatization procedures are under development with a view to increasing the scope for rapid determination of highly polar compounds that have previously proved difficult to analyze. Large volume injection techniques and developments in enzyme-linked immunosorbent assay (ELISA) technologies... 

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