A Device for Non-invasive On-site Sampling of Cattle Breath with Solid-Phase Microextraction

Non-invasive sampling and chemical analysis of breath gases could provide valuable information related to health and well-being. Breath gases are indicators of metabolic end products. The objective of this research was to design, assemble and test a new facemask-like device for on-site bovine breath sample collection with solid-phase microextraction (SPME). The new device consists of a cylindrical container, a sealing membrane for enclosure of nostrils and mouth of cattle, a system of filters and one-way valves, and sampling ports sealed with septa facilitating insertion of air sampling probes inside the device. An experiment was conducted to examine the feasibility of detecting volatile organic compounds (VOCs) exhaled by calves using this device. Solid-phase microextraction was used to collect rapid on-site breath samples. Divinylbenzene/Carboxen/polydimethylsiloxane (DVB/Carboxen/PDMS) 50/30 μm and PDMS 100 μm SPME fibres and sampling times ranging from 5 to 15 min were used. The SPME-based samples were sealed and transported to the laboratory and analysed with chromatography–mass spectrometry (GC–MS). Acetone, methyl ethyl ketone, toluene, tetradecane, pentadecane, nonanal and decanal were identified in cattle breath. A simple sampling system, combined with SPME-based sampling and analysis with GC–MS was very useful for fast collection and detection of bovine breath gases. The DVB/Carboxen/PDMS 50/30 μm fibre coating, sealing caps, and refrigeration worked well for retaining compounds found in breath samples. Solid-phase microextraction was also valuable for detection of residual VOCs in the breath sampling device that resulted in optimisation of cleaning procedures. The device can be easily adapted for other animals by adjusting the size of the cylindrical container and/or by replacing the sealing membrane with more suitable opening.