Abstract
A sensitive trace gas sensor platform based on quartz-enhanced photoacoustic spectroscopy (QEPAS) is reported. A 1.395 μm continuous wave (CW), distributed feedback pigtailed diode laser was used as the excitation source and H2O was selected as the target analyte. Two kinds of quartz tuning forks (QTFs) with a resonant frequency (f0) of 30.72 kHz and 38 kHz were employed for the first time as an acoustic wave transducer, respectively for QEPAS instead of a standard QTF with a f0 of 32.768 kHz. The QEPAS sensor performance using the three different QTFs was experimentally investigated and theoretically analyzed. A minimum detection limit of 5.9 ppmv and 4.3 ppmv was achieved for f0 of 32.768 kHz and 30.72 kHz, respectively.
Highlights
Trace gas sensor technologies are widely used in many applications, such as atmospheric chemistry [1,2], life science [3], medical diagnostics [4] and planetary exploration [5]
The quartz-enhanced photoacoustic spectroscopy (QEPAS) signal amplitude increased with the modulation depth, but when the modulation depth was higher than
A compact H2O QEPAS sensor using a 1.395 μm, pigtailed, continuous wave (CW) DFB diode laser was demonstrated as an excitation source
Summary
Trace gas sensor technologies are widely used in many applications, such as atmospheric chemistry [1,2], life science [3], medical diagnostics [4] and planetary exploration [5]. Trace gas sensor platforms based on near-infrared laser absorption spectroscopy have been reported in recent years [6,7,8,9,10]. Among these methods, photoacoustic spectroscopy (PAS) is an effective trace gas sensor technology which employs a broadband microphone for acoustic wave detection. The intensity of the acoustic wave is related to the sample concentration which can be detected by a sensitive microphone. Most microphone-based PAS cells have a low resonance frequency, which makes cells more sensitive to environmental and sample gas flow noise. The size of the typical photoacoustic cell is relatively large [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
