A NONREBREATHING BREATH COLLECTION SYSTEM FOR THE STUDY OF EXOGENOUS AND ENDOGENOUS COMPOUNDS IN THE FISHER-344 RAT

A nose-only, nonrebreathing breath collection system for use with Fish er-344 rats was developed and characterized. The system is open in des ign and relies on mass now controllers to regulate both the introducti on of clean, humidified air and the withdrawal of exhaled breath in a balanced fashion, The system accommodates simultaneous collection from three rats held in Battelle-type restrainers modified to include an a uxiliary nitrogen purge to minimize the infiltration of volatile organ ic compounds (VOCs) from the room and excreta into the collected breat h, The VOCs in breath were collected onto Tenax or multisorbent cartri dges and analyzed by thermal desorption/gas chromatography with flame ionization or mass spectrometric detection, Recoveries through the col lection and analysis system for a mixture of chemically diverse standa rd compounds at 4-10 ng/L each averaged 98%. The administration of car bon tetrachloride dramatically increased the number and amount of VOCs in breath, Increases were measured for hydrocarbons, aldehydes, keton es, and chlorinated species. The composition of these VOCs in breath w as observed to be time dependent.