The Mason Metabolomics Facility
Volatile Metabolites
Volatile organic compounds (VOCs) are a large and highly diverse group of carbon-based molecules, generally related by their volatility at ambient temperature. The diagnostic potential of VOCs in biological specimens has begun to receive considerable attention and correlations between the VOC metabolome and various diseases are emerging, including diabetes, asthma, cancer, and gastrointestinal disease. Specialized sampling methods, such as headspace solid phase microextraction (hSPME), have greatly facilitated the isolation of VOCs from biological specimens. A typical hSPME analysis involves the extraction of the VOCs via partitioning into a polymeric coating adhered to a fused silica rod (fiber), subsequent desorption of the VOCs by heating the fiber in the injection port of a gas chromatograph, separation of the VOCs by gas-liquid partition chromatography (GC), and detection of the VOCs via MS. Comparison to a mass spectral library permits the identification of the extracted analytes. While the polarity of the analyte of interest is typically used to guide the selection of a particular SPME fiber, we recently have shown that the multifarious nature of human biological sample composition dictates the use of multiple SPME fibers for maximal metabolomic coverage of the total VOCs. While this greatly increases metabolite inclusion, multiple sample extractions are then required, greatly increasing overall sample processing. To address this issue, we have developed and patented an innovative device that permits us to perform simultaneous multifiber extractions of a biological sample (“simulti-hSPME”). The device accommodates all of the commercially available fiber types simultaneously, ensuring maximal VOC metabolome coverage, while dramatically increasing the throughput of a VOC metabolomics investigation.
An Example VOC Study:
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