Patent ID: 7118537

Claim:
A method for collecting condensate from the breath of a subject inhaled through and exhaled into a portable device comprising a mouthpiece including a check valve optionally attached to a filter assembly further attached to the bottom end of a cooled, open-ended, hollow collecting tube close to the bottom end of which a hollow duckbill valve has been inserted so as to make a sealing connection with the interior walls thereof and for analyzing the collected condensate for the presence of one or more selected substances comprising: sliding a cooling sleeve having a lower temperature than the collecting tube over the collecting tube and placing the cooling sleeve in at least close physical proximity with the collecting tube prior to giving the tube to the subject; instructing the subject to inhale through the mouthpiece while ensuring by means of operation of the duckbill valve and a check valve located within the mouthpiece that air inhaled by the subject comes directly from a desired source and does not contaminate the collecting tube; directing the subject to exhale through the mouthpiece while maintaining the collecting tube oriented approximately perpendicular to the ground; channeling breath exhaled from the subject by means of closure of the check valve through the filter assembly, if there is one, and the duckbill valve turbulently into the collecting tube; repeating returning to the instructing step until a period of approximately ten minutes has elapsed from the first inhalation; removing the cooling sleeve from around the collecting tube and disconnecting the filter, if any, and mouthpiece assembly from the bottom end of the collecting tube; pushing the duckbill valve along the length of the collecting tube to within approximately two inches of the top end thereof while maintaining the collecting tube oriented approximately perpendicular to the ground so as to wipe condensate from the interior walls of the collecting tube and form a pool of condensate around the base of the duckbill valve; installing an airtight cap on the top end of the collecting tube if the tube is to be either stored for later use or shipped to another location for analysis; moving the tube to the analysis site and removing the airtight cap, if one has been installed; degassing the condensate pool; and withdrawing a test sample of the condensate for analysis.