Fig 1. Explanation of the sampling procedure and the VOCs measurement by IMR-MS.

A) breath sampler with disposable cardboard mouthpiece and the pushrod; B) connect the pushrod to the sampler and flush the sampler by pulling and pushing the rod in and out two or three times; C) remove to rod and connect the disposable mouthpiece to the sampler, placing the glass vial on the other side; D) have the patient breath normally and then keep exhaling trough the mouthpiece until their lungs are emptied; E) crimp airtight the glass vial with the appropriate crimp cap; F) throw away disposable mouthpiece and clean the breath sampler by flushing it two/three times using the pushrod; G) the glass vial, preserved at –20°C, is analyzed with the IMR-MS method, schematized here (reported from Defoort and colleagues [35]) and described in detail in Hornuss and colleagues [36].