Development of a membrane inlet mass spectrometer (MIMS) for environmental monitoring & other applications

Online monitoring of analytes in marine environments is receiving increased attention for a range of applications, including detection of pollutants in water. Major pollutants in water include volatile organic compounds (VOCs), dissolved gases and other naturally produced or anthropogenic toxic compounds. In addition to being a concern to environmental protection agencies, VOCs are also of interest to the oceanographic and atmospheric community as they are found to be important contributors to climate change, global warming and oxidant formation (smog). One of the well-established techniques for detecting traces of organic compounds in aqueous solutions is membrane inlet mass spectrometry (MIMS). The technique is simple (no need for pre-connection), sensitive (detection limits are in the ppb range) and able to analyse multi-component mixtures simultaneously and in a few minutes. The aim of this research is to investigate, design, produce and test a novel, sensitive, fast, safe, state-of-art membrane inlet probe and couple this to an existing mass spectrometer so as to allow mass spectrometry in harsh or demanding environments as well as using the system for detection of volatile orgamc compounds in aqueous samples or monitoring trace organics in water. In this work, also a novel comprehensive approach for simulating MIMS systems by calculating spectral characteristics of toxic VOCs in water, such as benzene, toluene and chloroform is presented. For comparison to experimental data, MIMS system consists of a membrane sample inlet, coupled to a portable quadrupole mass spectrometer (QMS) system with m/z 1-200 mass range. The QMS is characterized for monitoring analyte concentrations from 1 - 1000 ppm. Using the multi-ion trajectory simulation program QMS-2, developed by the University of Liverpool, the performance of the complete MIMS system including the membrane inlet probe and the QMS were simulated. The simulated results are compared with experimental ones showing good agreement for different analyte concentrations at room temperature.EThOS - Electronic Theses Online ServiceGBUnited Kingdo