SHEET MATERIALS FOR USE AS MEMBRANES IN MEMBRANE INTRODUCTION MASS-SPECTROMETRY

Several polymer sheets including silicone, latex, PVC, Tenon, polyuret hane, polyimide, polyethylene, and nitrile were used as membranes for membrane introduction mass spectrometry (MI/MS), The relative performa nce of each material was explored for its potential utility in MI/MS a nalyses where samples are delivered via now injection, Each of the mem brane materials was tested by exposing it to separate aqueous solution s containing the analytes benzene and ethanol in order to represent th e results that may be achieved for environmental analyses and fermenta tion monitoring, respectively. mow injection delivery of these solutio ns was used to measure the relative analyte quantification limits, res ponse times, and permeation of water as a function of temperature for each membrane material, It was observed that latex and polyurethane me mbranes yield MI/MS performance characteristics (in aqueous matrix) si milar to those of the commonly used silicone membranes for both benzen e and ethanol solutions, Polyethylene was observed to work well with b enzene as an analyte and simultaneously provided improved selectivity over water, While the other materials allowed aqueous matrix MI/MS to be performed, poor quantification limits and/or slow response times ma de these materials undesirable for this purpose, Two membrane material s which showed especially low organic permeability and higher water pe rmeability, polyimide and Tenon, were briefly tested with polar analyt es and nonpolar solvent. For the polyimide material, the analytes acet one, acetic acid, chloroform, ethanol, ethyl acetate, and water were r eadily observed in hexane solvent.