title: Measurement of acetaldehyde in exhaled breath using a laser absorption spectrometer.
abstract: A high-resolution liquid-nitrogen-free mid-infrared tunable diode laser absorption spectroscopy (TDLAS) system was used to perform real-time measurement of acetaldehyde concentrations in human exhaled breath following ingestion of an alcoholic beverage. Acetaldehyde absorption features were measured near 5.79 mum (1727 cm(-1)) using a IV-VI semiconductor laser, a 100 m long path optical gas cell, and second- harmonic detection coupled with wavelength modulation. Acetaldehyde levels were measured with a minimum detection limit of 80 ppb for 5 s integration time. The variations in exhaled acetaldehyde levels over time were analyzed prior to and following ingestion of two different amounts of white wine. A method to calibrate acetaldehyde measurements internally using water vapor absorption lines was investigated to eliminate the need for system calibration with gas standards. The potential of a TDLAS system to be used as a noninvasive clinical tool for measurements of large volatile compounds with possible applications in cancer detection is demonstrated.
authors.affiliation: Ekips Technologies, Incorporated, Norman, Oklahoma 73069, USA.
authors.forename: Pratyuma C
authors.initials: PC
authors.lastname: Kamat
authors.forename: Chad B
authors.initials: CB
authors.lastname: Roller
authors.forename: Khosrow
authors.initials: K
authors.lastname: Namjou
authors.forename: James D
authors.initials: JD
authors.lastname: Jeffers
authors.forename: Ali
authors.initials: A
authors.lastname: Faramarzalian
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Salas
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: McCann
mesh_terms: D000042:Absorption; D000079:Acetaldehyde / Q000032:analysis* / Q000737:chemistry; D001944:Breath Tests; D002138:Calibration; D005740:Gases; D006801:Humans; D007834:Lasers; D008962:Models, Theoretical; D055095:Optics and Photonics; D013053:Spectrophotometry; D013055:Spectrophotometry, Infrared; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D005740:Gases; D014867:Water; D000079:Acetaldehyde