Sensitive and accurate analysis of volatile organic compounds (VOCs) for medical and industrial purposes is currently a consuming process involving expensive mass spectrometric systems. In this study, we have developed and optimized a novel Total Internal Reflection (TIR) Raman spectroscopy system that enables VOC detection in the low ppm range. This system uses commercially available polymer sorbents to collect gaseous VOCs then thermally desorbs them where they partition into a thin polymer film coating within the Raman system for spectral analysis via evanescent wave excitation. We perform two-dimensional correlation analysis on time series spectra to sharpen VOC spectra while reducing interfering spectral features, and proof of principle has been established through analysis of known VOC biomarkers for selected bacterial pathogens relating to diseases such as ventilator-associated pneumonia. Integration of a position-sensitive detector measuring the position of the reflected beam exiting the TIR-Raman system has displayed changes in the refractive index of the polymer film coinciding with Raman spectra evidence of VOC absorption and desorption. We anticipate that our low-cost, robust system can be used for a variety of medical and industrial applications.

Building and optimizing a TIR-Raman spectroscopy system for volatile organic chemical analysis

254th National Meeting (2017)

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