scholarly journals A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

2016 ◽  
Vol 9 (2) ◽  
pp. 423-440 ◽  
Author(s):  
K.-E. Min ◽  
R. A. Washenfelder ◽  
W. P. Dubé ◽  
A. O. Langford ◽  
P. M. Edwards ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Cross Sections ◽  
Nitrous Acid ◽  
Aircraft Measurements ◽  
Charge Coupled Device ◽  
Light Emitting ◽  
Enhanced Absorption ◽  
Field Campaigns ◽  
A Charge ◽  
Absorption Spectrometer

Abstract. We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361–389 and 438–468 nm, using two light-emitting diodes (LEDs) and a single grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high-power LEDs with electronic on/off modulation, high-reflectivity cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350, and 80 parts per trillion (pptv) in 5 s. The accuracy is 5.8, 9.0, and 5.0 %, limited mainly by the available absorption cross sections.

scholarly journals A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

2015 ◽  
Vol 8 (10) ◽  
pp. 11209-11254 ◽  
Author(s):  
K.-E. Min ◽  
R. A. Washenfelder ◽  
W. P. Dubé ◽  
A. O. Langford ◽  
P. M. Edwards ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Cross Sections ◽  
Nitrous Acid ◽  
Aircraft Measurements ◽  
Charge Coupled Device ◽  
Light Emitting ◽  
Enhanced Absorption ◽  
Field Campaigns ◽  
A Charge ◽  
Absorption Spectrometer

Abstract. We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361–389 and 438–468 nm, using two light emitting diodes (LEDs) and a grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high power LEDs with electronic on/off modulation, state-of-the-art cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350 and 80 pptv in 5 s. The accuracy is 5.8, 9.0 and 5.0 % limited mainly by the available absorption cross sections.

scholarly journals Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer

2008 ◽  
Vol 8 (4) ◽  
pp. 16517-16553 ◽  
Author(s):  
R. A. Washenfelder ◽  
A. O. Langford ◽  
H. Fuchs ◽  
S. S. Brown
Keyword(s):  
Rayleigh Scattering ◽  
Optical Cavity ◽  
Field Measurements ◽  
Array Detector ◽  
Enhanced Absorption ◽  
Minimum Detectable Absorption ◽  
Wide Range ◽  
Path Lengths ◽  
A Charge ◽  
Absorption Spectrometer

Abstract. We describe an instrument for simultaneous measurements of glyoxal (CHOCHO) and nitrogen dioxide (NO2) using cavity enhanced absorption spectroscopy with a broadband light source. The output of a Xenon arc lamp is coupled into a 1 m optical cavity, and the spectrum of light exiting the cavity is recorded by a grating spectrometer with a charge-coupled device (CCD) array detector. The mirror reflectivity and effective path lengths are determined from the known Rayleigh scattering of He and dry zero air (N2+O2). Least-squares fitting, using published reference spectra, allow the simultaneous retrieval of CHOCHO, NO2, O4, and H2O in the 441 to 469 nm spectral range. For a 1-min sampling time, the minimum detectable absorption is 4×10−10 cm−1, and the precision (±1σ) on signal for measurements of CHOCHO and NO2 is 29 pptv and 20 pptv, respectively. We directly compare the incoherent broadband cavity enhanced absorption spectrometer to 404 and 532 nm cavity ringdown instruments for CHOCHO and NO2 detection, and find linear agreement over a wide range of concentrations. The instrument has been tested in the laboratory with both synthetic and real air samples, and the demonstrated sensitivity and specificity suggest a strong potential for field measurements of both CHOCHO and NO2.

scholarly journals Portable Spectrophotometer Using a White-Color Light-Emitting Diode and a Charge-Coupled Device and Its Application to On-Site Determination of Iron.

2000 ◽  
Vol 16 (10) ◽  
pp. 1091-1093 ◽  
Author(s):  
Yasutada SHIMAZAKI ◽  
Shunjiro WATANABE ◽  
Minori TAKAHASHI ◽  
Masaaki IWATSUKI
Keyword(s):  
Light Emitting Diode ◽  
Charge Coupled Device ◽  
Light Emitting ◽  
A Charge

scholarly journals Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer

2008 ◽  
Vol 8 (24) ◽  
pp. 7779-7793 ◽  
Author(s):  
R. A. Washenfelder ◽  
A. O. Langford ◽  
H. Fuchs ◽  
S. S. Brown
Keyword(s):  
Rayleigh Scattering ◽  
Optical Cavity ◽  
Field Measurements ◽  
Array Detector ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy ◽  
Wide Range ◽  
Path Lengths ◽  
A Charge ◽  
Absorption Spectrometer

Abstract. We describe an instrument for simultaneous measurements of glyoxal (CHOCHO) and nitrogen dioxide (NO2) using cavity enhanced absorption spectroscopy with a broadband light source. The output of a Xenon arc lamp is coupled into a 1 m optical cavity, and the spectrum of light exiting the cavity is recorded by a grating spectrometer with a charge-coupled device (CCD) array detector. The mirror reflectivity and effective path lengths are determined from the known Rayleigh scattering of He and dry zero air (N2+O2). Least-squares fitting, using published reference spectra, allow the simultaneous retrieval of CHOCHO, NO2, O4, and H2O in the 441 to 469 nm spectral range. For a 1-min sampling time, the precision (±1σ) on signal for measurements of CHOCHO and NO2 is 29 pptv and 20 pptv, respectively. We directly compare measurements made with the incoherent broadband cavity enhanced absorption spectrometer with those from cavity ringdown instruments detecting CHOCHO and NO2 at 404 and 532 nm, respectively, and find linear agreement over a wide range of concentrations. The instrument has been tested in the laboratory with both synthetic and real air samples, and the demonstrated sensitivity and specificity suggest a strong potential for field measurements of both CHOCHO and NO2.

Chemiluminescent and bioluminescent techniques

1991 ◽  
Vol 37 (9) ◽  
pp. 1472-1481 ◽  
Author(s):  
L J Kricka
Keyword(s):  
Alkaline Phosphatase ◽  
Light Emission ◽  
Renilla Luciferase ◽  
Photographic Film ◽  
Diverse Range ◽  
Charge Coupled Device ◽  
Light Emitting ◽  
Analytical System ◽  
A Charge ◽  
Glucose 6 Phosphate Dehydrogenase

Abstract Light-emitting chemical reactions (chemiluminescence, CL) and biological reactions (bioluminescence, BL) have a diverse range of analytical applications but relatively few have been adopted by routine clinical laboratories. Advantages of CL and BL assays include sensitivity (attomole and sub-attomole detection limits), speed (signal generated in a few seconds and in some cases stable for several hours), nonhazardous reagents, and simple procedures. The most promising clinical applications are in immunoassay, protein blotting, and DNA probe assays. Chemiluminescent molecules exploited as labels include luminol, isoluminol, acridinium esters, thioesters and sulfonamides, and phenanthridinium esters. Separation and nonseparation assays have been devised, based on isoluminol and acridinium ester labels. The combination of the amplification properties of an enzyme and a CL or BL detection reaction provides a highly sensitive analytical system. Since 1983, CL and BL methods have been developed for many enzyme labels, e.g., alkaline phosphatase, glucose-6-phosphate dehydrogenase, horseradish peroxidase, Renilla luciferase, and xanthine oxidase. Currently, the most successful enzyme assays are the enhanced CL method for a peroxidase label involving a mixture of luminol, hydrogen peroxide, and an enhancer (e.g., p-iodophenol) and the direct CL method for alkaline phosphatase, with an adamantyl 1,2-dioxetane phenyl phosphate as substrate. Both systems are very sensitive (the detection limit for alkaline phosphatase when using the dioxetane reagent is 0.001 amol) and produce long-lived light emission (greater than 30 min), which is ideal for membrane applications in which light emission is detected with photographic film or a charge-coupled device camera.

Dual-channel incoherent broadband cavity-enhanced absorption spectrometer for sensitive atmospheric NOx measurements.

The Analyst ◽  
2021 ◽  
Author(s):  
Anoop Pakkattil ◽  
Aiswarya Saseendran ◽  
Arun. P. Thomas ◽  
Anjana. S. Raj ◽  
Ardra Mohan ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Nitrogen Monoxide ◽  
Enhanced Absorption ◽  
Dual Channel ◽  
Absorption Spectrometer

We describe and characterize a dual-channel incoherent broadband cavity-enhanced absorption spectrometer (DC-IBBCEAS) for the sensitive measurements of NOx; the sum of nitrogen monoxide (NO) and nitrogen dioxide (NO2) in the...

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