title: Electronic Nose for Recognition of Volatile Vapor Mixtures Using a Nanopore-Enhanced Opto-Calorimetric Spectroscopy.
abstract: An electronic nose (e-nose) for identification and quantification of volatile organic compounds (VOCs) vapor mixtures was developed using nanopore-enhanced opto-calorimetric spectroscopy. Opto-calorimetric spectroscopy based on specific molecular vibrational transitions in the mid infrared (IR) "molecular fingerprint" regime allows highly selective detection of VOCs vapor mixtures. Nanoporous anodic aluminum oxide (AAO) microcantilevers, fabricated using a two-step anodization and simple photolithography process, were utilized as highly sensitive thermomechanical sensors for opto-calorimetric signal transduction. The AAO microcantilevers were optimized by fine-tuning AAO nanopore diameter in order to enhance their thermomechanical sensitivity as well as their surface area. The thermomechanical sensitivity of a bilayer AAO microcantilever with a 60 nm pore diameter was approximately 1 μm/K, which is far superior to that of a bilayer plain silicon (Si) microcantilever. The adsorbed molecules of VOCs mixtures on the AAO microcantilever were fully recognized and quantified by variations of peak positions and amplitudes in the opto-calorimetric IR spectra as well as by shifts in the resonance frequency of the AAO microcantilever with the adsorbed molecules. Furthermore, identification of complex organic compounds with a real industrial sample was demonstrated by this e-nose system.
authors.affiliation: †Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.
authors.forename: Inseok
authors.initials: I
authors.lastname: Chae
authors.affiliation: †Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.|§Daegu Research Center for Medical Devices, Korea Institute of Machinery and Materials, Daegu 711-880, Republic of Korea.
authors.forename: Dongkyu
authors.initials: D
authors.lastname: Lee
authors.affiliation: ‡Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
authors.forename: Seonghwan
authors.initials: S
authors.lastname: Kim
authors.affiliation: †Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Thundat
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D015374:Biosensing Techniques; D002151:Calorimetry; D062609:Electronic Nose; D005740:Gases / Q000737:chemistry*; D058608:Nanopores; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D005740:Gases; D055549:Volatile Organic Compounds; D000537:Aluminum Oxide