title: Real-time monitoring of ozone in air using substrate-integrated hollow waveguide mid-infrared sensors.
abstract: Ozone is a strong oxidant that is globally used as disinfection agent for many purposes including indoor building air cleaning, during food preparation procedures, and for control and killing of bacteria such as E. coli and S. aureus. However, it has been shown that effective ozone concentrations for controlling e.g., microbial growth need to be higher than 5 ppm, thereby exceeding the recommended U.S. EPA threshold more than 10 times. Consequently, real-time monitoring of such ozone concentration levels is essential. Here, we describe the first online gas sensing system combining a compact Fourier transform infrared (FTIR) spectrometer with a new generation of gas cells, a so-called substrate-integrated hollow waveguide (iHWG). The sensor was calibrated using an UV lamp for the controlled generation of ozone in synthetic air. A calibration function was established in the concentration range of 0.3-5.4 mmol m⁻³ enabling a calculated limit of detection (LOD) at 0.14 mmol m⁻³ (3.5 ppm) of ozone. Given the adaptability of the developed IR sensing device toward a series of relevant air pollutants, and considering the potential for miniaturization e.g., in combination with tunable quantum cascade lasers in lieu of the FTIR spectrometer, a wide range of sensing and monitoring applications of beyond ozone analysis are anticipated.
authors.affiliation: 1] São Paulo State University, Department of Analytical Chemistry, UNESP, CEP 14800-970, Araraquara, SP, Brazil [2] University of Ulm, Institute of Analytical and Bioanalytical Chemistry, 89081, Ulm, Germany.
authors.forename: João Flávio
authors.initials: JF
authors.lastname: da Silveira Petruci
authors.forename: Paula Regina
authors.initials: PR
authors.lastname: Fortes
authors.forename: Vjekoslav
authors.initials: V
authors.lastname: Kokoric
authors.forename: Andreas
authors.initials: A
authors.lastname: Wilk
authors.forename: Ivo Milton
authors.initials: IM
authors.lastname: Raimundo
authors.forename: Arnaldo Alves
authors.initials: AA
authors.lastname: Cardoso
authors.forename: Boris
authors.initials: B
authors.lastname: Mizaikoff
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000592:standards; D002138:Calibration; D004202:Disinfectants / Q000032:analysis* / Q000592:standards; D010126:Ozone / Q000032:analysis* / Q000592:standards; D017550:Spectroscopy, Fourier Transform Infrared / Q000592:standards; D014466:Ultraviolet Rays
chemical_list: D000393:Air Pollutants; D004202:Disinfectants; D010126:Ozone