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Novel extraction of volatile biomarkers from canine breath for gas chromatography–mass spectrometry

Here we describe an effective, reproducible, non-invasive volatile organic compound collection and analysis method for exhaled breath gas samples designed specifically for use with dogs. Conditions of the method were optimized, using a range of standard chemicals. This method utilizes a canine mask, two-way non-re-breathing valve, teflon connector, tubing and bag for sample collection. Collection is followed by condensation and headspace solid phase microextraction for sample concentration and gas chromatography–mass spectrometry for analysis. Custom-made glassware, designed to hold the SPME fiber assembly, was cooled to −10 °C and used for the collection of the condensate followed by 2 h of headspace extraction at 37 °C. Standards show LOD of 0.6–16.8 ppbv, LOQ between 2.1–55.8 ppbv, and good linearity with R2 between 0.996–0.999 (RSD% 10–19). The method was verified with preliminary results from three dogs demonstrating that this technique is capable of collecting, identifying and quantifying volatile organic chemical constituents in different breath samples.