Characterisation of a Novel Field Asymmetric Ion Mobility Spectrometer and its Evaluation for Non-Traditional Applications
Published on 11 Feb 13
Here are copies of Dr. Andrew Morris' recently completed PhD thesis (entitled "Characterisation of a Novel Field Asymmetric Ion Mobility Spectrometer and its Evaluation for Non-Traditional Applications" ) and a conference paper ( "In-situ monitoring of compounds in planetary atmospheres using a miniaturized field asymmetric ion mobility spectrometer" ). Dr. Morris studied for his PhD at the Planetary and Space Sciences Research Institute (PSSRI) at The Open University and was sponsored by Owlstone Ltd. Congratulations Andrew from everyone at Owlstone!
Thesis abstract: Field asymmetric ion mobility spectrometry (FAIMS) is an atmospheric pressure analysis technique that is suitable for miniaturisation. Owlstone Ltd. has developed a nanofabricated FAIMS sensor which possesses the smallest dimensions of any such device. Following a detailed review of the theory underpinning FAIMS two separate investigations were conducted to characterise and optimise the sensor’s performance. The first case study systematically characterised the effects of modifying the pressure, humidity and magnitude of the carrier flow through the sensor. Dimethylmethylphosphonate, a simulant for the nerve agent sarin, was selected for the study. The onset of clustering, a phenomenon within FAIMS, was observed and the relationships with the modified parameters of the carrier flow were rationalised. The second case study represented a new challenge for FAIMS - its application as a detector following the gas chromatographic separation of ethyl acetate from the main components of wine. Lessons learnt from the characterisation study were applied and as a result it was possible to negate the attenuating effects of ethanol. Ethyl acetate was successfully detected at concentrations below the human perception threshold. Peak fitting was also explored as a method to enhance the specificity of recorded ion responses and to enable automated interpretation of generated data. Three different methods were formulated, each proved more suitable to a particular scenario than the others. Systematic characterisation of this novel sensor, and its evaluation for non-traditional applications, has resulted in a deeper understanding of FAIMS, its limitations and capabilities. This has led to the development of new tools and methods which can aid investigations beyond these studies, ultimately enhancing the capability of the sensor for more diverse applications.