Sub-ppb detection of formaldehyde with cantilever enhanced photoacoustic spectroscopy using quantum cascade laser source

Hirschmann, Christian Bernd; Lehtinen, Jaakko; Uotila, Juho; Ojala, Satu; Keiski, Riitta L.

doi:10.1007/s00340-013-5379-4

Cited by 33 publications

(23 citation statements)

References 37 publications

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“…In recent years the number of reported photoacoustic (PA) instruments to prove their applicability in various areas has been steadily increasing [1][2][3][4]. Amongst these instruments are those which were developed by our research group for various applications, including in the natural gas industry [5][6][7], airborne hygrometry [8][9], source apportionment of urban light-absorbing aerosols [10][11], measurements of gas permeability [12], and clinical research [13].…”

Section: Motivationmentioning

confidence: 99%

Embedded system based data acquisition and control system for photoacoustic spectroscopic applications

Tátrai

Bozóki

Gulyas³

et al. 2015

Measurement

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Laser absorption spectroscopy by photoacoustic (PA) detection technique is increasingly used in trace gas analysis. Our research group focuses on related instrument and application development. In this paper the design and test results of a newly developed field programmable gate array based data acquisition and control system (DACS), are introduced. It became necessary to develop this new system since the limits of the old one had been reached; furthermore, it was challenging to implement new advanced measuring protocols. The system was designed to be scalable in order to be able to implement further ideas or measurement protocols without significant hardware or software modifications. In the current configuration, approximately 60% of the resources of the system are used. A complete PA measuring system was built around the new DACS to determine the analytical properties: the normalized noise equivalent absorption is 7.5 Â 10 À10 cm À1 W Hz À1/2 , while the estimated dynamic range for measuring optical absorption is 7.5 orders of magnitude.

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Section: Motivationmentioning

confidence: 99%

Embedded system based data acquisition and control system for photoacoustic spectroscopic applications

Tátrai

Bozóki

Gulyas³

et al. 2015

Measurement

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“…Quantum cascade lasers have mainly been utilized in the measurement of trace gases in photoacoustic spectroscopy (PAS) [3,5,6]. Also, a few research groups have made studies with solids [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Broadly tunable quantum cascade laser in cantilever-enhanced photoacoustic infrared spectroscopy of solids

Lehtinen

Kuusela

2013

Appl. Phys. B

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An external cavity quantum cascade laser (EC-QCL) is applied in the photoacoustic detection of solid samples. The EC-QCL used has a broad tuning range of 676 cm -1 (970-1,646 cm -1 ) in the mid-infrared region, which enables accurate broadband spectroscopy of large molecules. The high spectral power density of the EC-QCL is combined with an extremely sensitive optical cantilever microphone of the photoacoustic detector to achieve an ultimate sensitivity. The carbon black, polyethylene, and hair fiber samples were measured with the EC-QCL photoacoustic detection using electrical amplitude modulation to demonstrate the possibilities of the setup. The same measurements were repeated with a Fourier transform infrared (FTIR) spectrometer combined with a photoacoustic detector for a comparison. The EC-QCL photoacoustic setup yielded roughly a decade better signalto-noise ratios than the FTIR setup with the same measurement time.

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“…Different instruments are used for the VOCs detection and quantification, such as gas chromatography, mass spectrometers [19], Fourier Transform Infra Red (FTIR) spectrometers [20], tunable diode laser spectrometers (TDLS) [21] and photoacoustic-based TDLS [22]. TDLS and photoacoustic-based TDLS are characterized by high sensitivity and selectivity compared to FTIR spectroscopy, however, FTIR spectroscopy has a much larger spectral range which means the capability of measurement of a wide variety of different gases at the same time.…”

Section: Introductionmentioning

confidence: 99%

Continuous Monitoring of Air Purification: A Study on Volatile Organic Compounds in a Gas Cell

Fathy

Pivert

Kim

et al. 2020

Sensors

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Air pollution is one of the major environmental issues that humanity is facing. Considering Indoor Air Quality (IAQ), Volatile Organic Compounds (VOCs) are among the most harmful gases that need to be detected, but also need to be eliminated using air purification technologies. In this work, we tackle both problems simultaneously by introducing an experimental setup enabling continuous measurement of the VOCs by online absorption spectroscopy using a MEMS-based Fourier Transform infrared (FTIR) spectrometer, while those VOCs are continuously eliminated by continuous adsorption and photocatalysis, using zinc oxide nanowires (ZnO-NWs). The proposed setup enabled a preliminary study of the mechanisms involved in the purification process of acetone and toluene, taken as two different VOCs, also typical of those that can be found in tobacco smoke. Our experiments revealed very different behaviors for those two gases. An elimination ratio of 63% in 3 h was achieved for toluene, while it was only 14% for acetone under same conditions. Adsorption to the nanowires appears as the dominant mechanism for the acetone, while photocatalysis is dominant in case of the toluene.

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Sub-ppb detection of formaldehyde with cantilever enhanced photoacoustic spectroscopy using quantum cascade laser source

Cited by 33 publications

References 37 publications

Embedded system based data acquisition and control system for photoacoustic spectroscopic applications

Embedded system based data acquisition and control system for photoacoustic spectroscopic applications

Broadly tunable quantum cascade laser in cantilever-enhanced photoacoustic infrared spectroscopy of solids

Continuous Monitoring of Air Purification: A Study on Volatile Organic Compounds in a Gas Cell

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