Uncovering hidden compositional changes in breath profiles using TD–GC×GC–TOF MS and untargeted chemometric workflows
Laura McGregor, Ryan Sutherill and Bob Green
SepSolve Analytical, 4 Swan Court, Cygnet Park, Peterborough, PE7 8GX, UK.
Thermal desorption (TD) coupled with GC-MS is known as the ‘gold standard’ for breath biomarker analysis, due to its ability to collect a comprehensive breath profile with high confidence and sample security. However, one of the key challenges in breath analysis is that hundreds of different VOCs can be present, often at trace levels – making it difficult to isolate and identify biomarkers of disease. Here we demonstrate the use of GC×GC–TOF MS for the enhanced separation necessary to resolve these complex mixtures and provide clean spectra for confident identification. We also show the use of a powerful data mining and chemometrics platform to automatically align the chromatograms and find the significant differences between the sample classes using all of the raw data. In metabolomics matrices, diagnostic compounds are rarely of high abundance – by utilising all of the raw data, trace differences are less likely to be overlooked. We will demonstrate how these innovative tools can allow automated untargeted workflows to be adopted, minimising laborious pre-processing steps and speeding up analytical workflows.