Development and application of an ion mobility spectometer - quadrupole mass spectometer instrument

摘要

The aim of the project described in this thesis was to develop a system in house that would be capable of providing a technique to enhance the reliability of detection of threat agents such as compounds used for chemical warfare and explosives. This was to be done by using a combination of an ion mobility spectrometer (IMS) in tandem with a quadrupole mass spectrometer (QMS). When meeting these requirements, the latest electronics and software were incorporated in the instrumentation to maximise sensitivity and flexibility.udBy attaching a QMS to an IMS, an extra dimension in specificity is gained whereby a more positive identification of a compound is made based on m/z values, thereby providing further information on the ion-molecule processes taking place in the IMS. Flexibility in operation was achieved by using the graphical programming language LabVIEW for the software aspects, allowing program development and modification to be made more quickly than would be the case than if a procedural language such as C++ had been used. udA special ‘pulse to analogue’ converter developed during the project provided increased sensitivity and resolution over earlier systems in regard to obtaining selected mass mobility spectra. udProof-of-principle measurements are provided that demonstrate the capabilities of the newly developed IMS-QMS system in both positive and negative ion modes of operation, with some results obtained that are consistent with those from previous investigations. udData obtained for various chemicals not previously investigated are also provided.