title: Chemical discrimination in turbulent gas mixtures with MOX sensors validated by gas chromatography-mass spectrometry.
abstract: Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance.
authors.affiliation: BioCircuits Institute, University of California San Diego, La Jolla, CA 92093, USA. fonollosa@ucsd.edu.
authors.forename: Jordi
authors.initials: J
authors.lastname: Fonollosa
authors.affiliation: BioCircuits Institute, University of California San Diego, La Jolla, CA 92093, USA.
authors.forename: Irene
authors.initials: I
authors.lastname: Rodríguez-Luján
authors.affiliation: AASS Research Center, Örebro University, 70281, Örebro, Sweden. marco.trincavelli@oru.se.
authors.forename: Marco
authors.initials: M
authors.lastname: Trincavelli
authors.affiliation: Biomolecular Measurement Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899-8362, USA. vergara@ucsd.edu.
authors.forename: Alexander
authors.initials: A
authors.lastname: Vergara
authors.affiliation: BioCircuits Institute, University of California San Diego, La Jolla, CA 92093, USA. rhuerta@ucsd.edu.
authors.forename: Ramón
authors.initials: R
authors.lastname: Huerta
mesh_terms: D000388:Air; D000393:Air Pollutants / Q000737:chemistry / Q000302:isolation & purification*; D008401:Gas Chromatography-Mass Spectrometry; D005740:Gases / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D060388:Support Vector Machine
chemical_list: D000393:Air Pollutants; D005740:Gases