Ultra-sensitive ammonia detection for industrial applications using photoacoustic spectroscopy

2002 ◽  
Author(s):  
Michael Webber ◽  
Michael B. Pushkarsky ◽  
Ohan Baghdassarian ◽  
L. Ravi Narasimhan ◽  
C. Kumar N. Patel
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Industrial Applications ◽  
Ammonia Detection

scholarly journals High Sensitivity Continuous Monitoring of Chloroform Gas by Using Wavelength Modulation Photoacoustic Spectroscopy in the Near-Infrared Range

2021 ◽  
Vol 11 (15) ◽  
pp. 6992
Author(s):  
Tie Zhang ◽  
Yuxin Xing ◽  
Gaoxuan Wang ◽  
Sailing He
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Continuous Monitoring ◽  
Near Infrared ◽  
Resonant Cavity ◽  
High Sensitivity ◽  
Industrial Applications ◽  
Detection Sensitivity ◽  
Infrared Range ◽  
Wavelength Modulation ◽  
Linear Coefficient

An optical system for gaseous chloroform (CHCl3) detection based on wavelength modulation photoacoustic spectroscopy (WMPAS) is proposed for the first time by using a distributed feedback (DFB) laser with a center wavelength of 1683 nm where chloroform has strong and complex absorption peaks. The WMPAS sensor developed possesses the advantages of having a simple structure, high-sensitivity, and direct measurement. A resonant cavity made of stainless steel with a resonant frequency of 6390 Hz was utilized, and eight microphones were located at the middle of the resonator at uniform intervals to collect the sound signal. All of the devices were integrated into an instrument box for practical applications. The performance of the WMPAS sensor was experimentally demonstrated with the measurement of different concentrations of chloroform from 63 to 625 ppm. A linear coefficient R2 of 0.999 and a detection sensitivity of 0.28 ppm with a time period of 20 s were achieved at room temperature (around 20 °C) and atmosphere pressure. Long-time continuous monitoring for a fixed concentration of chloroform gas was carried out to demonstrate the excellent stability of the system. The performance of the system shows great practical value for the detection of chloroform gas in industrial applications.

scholarly journals Sup-ppb ammonia detection based on photoacoustic spectroscopy

2005 ◽  
Author(s):  
Jean P. Besson ◽  
Stephane Schilt ◽  
Luc Thevenaz
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Ammonia Detection

Ultra-sensitive ambient ammonia detection using CO2-laser-based photoacoustic spectroscopy

2003 ◽  
Vol 77 (4) ◽  
pp. 381-385 ◽  
Author(s):  
M.B. Pushkarsky ◽  
M.E. Webber ◽  
C.K.N. Patel
Keyword(s):  
Co2 Laser ◽  
Photoacoustic Spectroscopy ◽  
Ammonia Detection

Carbon dioxide and ammonia detection using 2 μm diode laser based quartz-enhanced photoacoustic spectroscopy

2006 ◽  
Vol 87 (1) ◽  
pp. 157-162 ◽  
Author(s):  
R. Lewicki ◽  
G. Wysocki ◽  
A.A. Kosterev ◽  
F.K. Tittel
Keyword(s):  
Carbon Dioxide ◽  
Diode Laser ◽  
Photoacoustic Spectroscopy ◽  
Ammonia Detection

Ammonia detection by using quantum-cascade laser photoacoustic spectroscopy

2006 ◽  
Vol 45 (20) ◽  
pp. 4966 ◽  
Author(s):  
Milton B. Filho ◽  
Marcelo G. da Silva ◽  
Marcelo S. Sthel ◽  
Delson U. Schramm ◽  
Helion Vargas ◽  
...  
Keyword(s):  
Quantum Cascade Laser ◽  
Photoacoustic Spectroscopy ◽  
Quantum Cascade ◽  
Laser Photoacoustic Spectroscopy ◽  
Ammonia Detection

scholarly journals Sub-ppm-Level Ammonia Detection Using Photoacoustic Spectroscopy with an Optical Microphone Based on a Phase Interferometer

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2890 ◽  
Author(s):  
Oscar E. Bonilla-Manrique ◽  
Julio E. Posada-Roman ◽  
Jose A. Garcia-Souto ◽  
Marta Ruiz-Llata
Keyword(s):  
Absorption Line ◽  
Photoacoustic Spectroscopy ◽  
Limit Of Detection ◽  
Second Harmonic ◽  
Laser Doppler Vibrometer ◽  
Fibre Laser ◽  
Harmonic Detection ◽  
Common Path ◽  
Ammonia Detection ◽  
Path Topology

A sensitive optical microphone for photoacoustic spectroscopy based on the common path topology of a fibre laser Doppler vibrometer (FLDV) using phase-generated carrier demodulation and a slim diaphragm as an acoustic wave transducer was demonstrated. A resonant gas cell was adapted to enhance gas-detection performance and simultaneously provide efficient cancellation of the window background acoustic signal. Ammonia (NH3) was selected as the target gas. The absorption line was experimentally identified using a distributed feedback laser diode emitting at 1530 nm. The linearity and sensitivity of the gas sensor were measured using wavelength modulation spectroscopy with second harmonic detection. A Teflon diaphragm was used to implement the optical microphone, along with the FLDV, showing a minimum detectable pressure of 79.5 μPa/Hz1/2. The noise-equivalent absorption sensitivity for NH3 detection at the absorption line at 1531.7 nm was 1.85 × 10−8 W cm−1 Hz−1/2, and the limit of detection was 785 ppbv.

The Application of Ultra-Thin Sectioning Techniques to Non-Biological Samples

1968 ◽  
Vol 26 ◽  
pp. 332-333
Author(s):  
C. F. Oster
Keyword(s):  
Biological Sciences ◽  
Epoxy Resin ◽  
Cross Sections ◽  
Biological Samples ◽  
Industrial Applications ◽  
Photographic Film ◽  
Silver Particles ◽  
Thin Sectioning ◽  
Embedding Medium

Although ultra-thin sectioning techniques are widely used in the biological sciences, their applications are somewhat less popular but very useful in industrial applications. This presentation will review several specific applications where ultra-thin sectioning techniques have proven invaluable.The preparation of samples for sectioning usually involves embedding in an epoxy resin. Araldite 6005 Resin and Hardener are mixed so that the hardness of the embedding medium matches that of the sample to reduce any distortion of the sample during the sectioning process. No dehydration series are needed to prepare our usual samples for embedding, but some types require hardening and staining steps. The embedded samples are sectioned with either a prototype of a Porter-Blum Microtome or an LKB Ultrotome III. Both instruments are equipped with diamond knives.In the study of photographic film, the distribution of the developed silver particles through the layer is important to the image tone and/or scattering power. Also, the morphology of the developed silver is an important factor, and cross sections will show this structure.

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