Breath analysis: methodology towards a fieldable breath analysis device
thesisposted on 23.06.2011, 15:10 by Gavin J. Blackburn
In this work lung cancer is introduced along with the current detection methods. The inadequacies of the current situation are highlighted along with the need for better detection technologies that would allow for a more rigorous testing regime to be implemented. Metabolism and metabolites are introduced as potential biomarkers. The advanced detection techniques mass spectrometry (MS) and differential mobility spectrometry (DMS) are introduced and discussed with regard to being a fieldable device. The methods applicable to processing data generated by these instruments are discussed. Finally the research objectives are highlighted. The science of breath sampling is discussed along with the considerations when engaging in breath analysis research. Sampling and trapping of volatile organic compounds (VOCs) is discussed with particular emphasis on the adaptive breath sampler which was used in this work. The benefits of a dual detector instrument allowing for analysis of a single sample using both MS and DMS are outlined. The design and implementation of a parallel, two detector system is outlined including the intricacies of balancing the two columns that operate at different pressures and developing a mount Processing DMS data currently lags behind the current hardware available as there are no methods that allow the full data surface to be utilised. This work outlines a method for transforming DMS data from three dimensions to two dimensions while retaining the full information contained within the data surface. This method was tested with generated data sets to show its’ utility and compared to the current standard processing method using real data sets. An understanding of all aspects of a clinical research project is vital to ensure the smooth running and completion of the project. The currently required documentation for an outside researcher to work within the NHS are detailed along with the expected timeframe for each step of designing, gaining ethical approval and implementing the research. The use of Gantt charts and work flow diagrams is highlighted and examples are given. An initial inspection of the data produced by a pilot study shows that there a several challenges that must be overcome, these are contamination and artefact peaks, retention time shifting, unresolved peaks, differing intensities in similar samples and the complexities of correctly identifying compounds found in breath samples. These are discussed and a workflow is highlighted.