title: Detection of Atmospheric Methyl Mercaptan Using Wavelength Modulation Spectroscopy with Multicomponent Spectral Fitting.
abstract: Detection of methyl mercaptan (CH₃SH) is essential for environmental atmosphere assessment and exhaled-breath analysis. This paper presents a sensitive CH₃SH sensor based on wavelength modulation spectroscopy (WMS) with a mid-infrared distributed feedback interband cascade laser (DFB-ICL). Multicomponent spectral fitting was used not only to enhance the sensitivity of the sensor but also to determine the concentration of interferents (atmospheric water and methane). The results showed that the uncertainties in the measurement of CH₃SH, H₂O, and CH₄ were less than 1.2%, 1.7% and 2.0%, respectively, with an integration time of 10 s. The CH₃SH detection limit was as low as 7.1 ppb with an integration time of 295 s. Overall, the reported sensor, boasting the merits of high sensitivity, can be used for atmospheric methyl mercaptan detection, as well as multiple components detection of methyl mercaptan, water, and methane, simultaneously.
authors.affiliation: State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China. duzhenhui@tju.edu.cn.
authors.forename: Zhenhui
authors.initials: Z
authors.lastname: Du
authors.affiliation: State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China. Melissaslove@sina.com.
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Wan
authors.affiliation: Key Laboratory of Advanced Electrical Engineering and Energy Technology, Tianjin Polytechnic University, Tianjin 300387, China. lijinyi@tjpu.edu.cn.
authors.forename: Jinyi
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China. luogang@tju.edu.cn.
authors.forename: Gang
authors.initials: G
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China. gaohongtju@tju.edu.cn.
authors.forename: Hong
authors.initials: H
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China. yiwenma@tju.edu.cn.
authors.forename: Yiwen
authors.initials: Y
authors.lastname: Ma
keywords: distributed feedback interband cascade laser (DFB-ICL); methyl mercaptan sensor; mid-infrared spectroscopy; multicomponent spectral fitting; wavelength modulation spectroscopy (WMS)