title: Quantum cascade laser-based photoacoustic spectroscopy for trace vapor detection and molecular discrimination.
abstract: We report on the development of a microelectromechanical systems (MEMS)-scale photoacoustic sensor for the detection of trace gases. A mid-infrared quantum cascade laser (QCL) was used to determine detection limits for acetic acid, acetone, 1,4-dioxane, and vinyl acetate. The source was continuously tunable from 1015 cm(-1) to 1240 cm(-1), allowing for the collection of photoacoustic vibrational spectra for these gases. Exceptional agreement between the measured photoacoustic spectra and the infrared spectra for acetic acid, acetone, 1,4-dioxane, and vinyl acetate was observed. Partial least-squares (PLS) regression was used to develop an algorithm for classification of these compounds based solely on photoacoustic spectra.
authors.affiliation: United States Army Research Laboratory, RDRL-SEE-O, 2800 Powder Mill Road, Adelphi, MD 20783, USA. ellen.holthoff@us.army.mil
authors.forename: Ellen
authors.initials: E
authors.lastname: Holthoff
authors.forename: John
authors.initials: J
authors.lastname: Bender
authors.forename: Paul
authors.initials: P
authors.lastname: Pellegrino
authors.forename: Almon
authors.initials: A
authors.lastname: Fisher
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000096:Acetone / Q000737:chemistry; D000465:Algorithms; D004146:Dioxanes / Q000737:chemistry; D005740:Gases / Q000032:analysis* / Q000145:classification; D054023:Lasers, Semiconductor; D016018:Least-Squares Analysis; D057230:Limit of Detection; D055617:Micro-Electrical-Mechanical Systems; D061088:Photoacoustic Techniques / Q000295:instrumentation / Q000379:methods; D013057:Spectrum Analysis / Q000379:methods*; D014753:Vinyl Compounds / Q000737:chemistry
chemical_list: D004146:Dioxanes; D005740:Gases; D014753:Vinyl Compounds; D000096:Acetone; C025223:1,4-dioxane; C011566:vinyl acetate; D019342:Acetic Acid