Chemiluminescent measurement of atmospheric ozone.  Response characteristics and operating variables

Hodgeson, Jimmie A.; Krost, K. J.; O'Keeffe, Andrew E.; Stevens, Robert K.

doi:10.1021/ac50160a056

Cited by 54 publications

(32 citation statements)

References 13 publications

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“…As shown in Figs. 2 (a) and (b), the subbands contained in the CL spectra emitted by the catalytic oxidation of ethanol have the same peak wavelengths independent of the type of the catalysts of γ-Al 2 O 3 and CaCO 3 . This implies that CL originates in excited molecules, which may be produced during some intermediate steps of the catalytic oxidation.…”

Section: Discussionmentioning

confidence: 96%

Detection of Organic Molecules Dissolved in Water Using a γ-Al2O3 Chemiluminescence-Based Sensor

1998

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Chemiluminescence measurement is a very useful method for detecting molecules. This method has high sensitivity, good reproducibility and selectivity, quick response and good linearity over a wide concentration region. However, it is not convenient for continuous and long-term detection, because a supply of reactants to produce luminescent species through a chemical reaction is required. Although many investigations have attempted to improve these disadvantages since 1960 1-4 , a long-term stability of the sensitivity has hardly been attained. A new possibility of a CL-based sensor which does not require a supply of reactants was proposed by Breysse et al. in 1976. 5 They observed CL during the catalytic oxidation of carbon monoxide on a thoria surface. In 1990, we found that CL is observed during the catalytic oxidation of organic vapors on an alumina surface. 7 These phenomena can be applied to CL-based sensors. Various methods to detect organic vapors in air have been reported elsewhere. [8][9][10][11] In this paper, we deal with a method used to detect organic molecules, e.g. acetone and ethanol, dissolved in water using this sensor. We will describe the elementary working mechanism of the sensor and its working condition under which the response is quick and stable. Figure 1 shows a schematic diagram of the measuring system for a CL-based sensor. The CL-based sensor is made of a sintered layer of γ-Al 2 O 3 powder with a thickness of 0.5 mm. The pasty mixture of the powder and aluminum nitrate solution of 2 M was laid on a ceramic substrate (3 mm×1.5 mm), and then heated at 900˚C for 2 h. The sensor was heated by an electric heater made of Pt film laid on the reverse side of the substrate. The sensor was placed in a quartz tube having two bundles of Teflon tubes of 1 mm in diameter at both ends of the tube in order to keep the movement of the gas around the sensor in a laminar flow. A sample solution containing organic molecules was placed in a vaporizer kept at a constant temperature. The vapor was mixed with synthesized air (a mixture of 21% oxygen and 79% nitrogen). The mixed gas at atmospheric pressure flowed through the quartz tube and was removed by a diaphragm pump. The mean-flow velocity of the sample gas in the tube (v) was controlled by a mass-flow controller. The chemiluminescence from the sensor was measured by a photomultiplier through optical filters using a photon-counting technique. For the CL spectrum measurements, a spectrometer was used instead of these filters. The CL intensity at each wavelength was measured at a resolution of 10 nm. The concentration of the organic molecules in the mixed gas was monitored by a mass spectrometer through a differential evacuating system. The results of a catalytic reaction on the sensor were also detected by the mass spectrometer. A new method is proposed for recognizing organic molecules dissolved in water using a chemiluminescence-based sensor made with a γ-Al2O3 catalyst. When a mixture of air and organic molecules, e.g. ethanol and acetone vaporize...

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Section: Discussionmentioning

confidence: 96%

Detection of Organic Molecules Dissolved in Water Using a γ-Al2O3 Chemiluminescence-Based Sensor

1998

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“…Hodgeson et al (1970) suggested (for compound rhodamine B) the mechanism for chemiluminescence is based on a resonance energy transfer where the initial ozone during activation reacts with the dye to produce a dye molecule in an excited singlet state which then emits upon second exposure to ozone. This would be consistent with the reported loss of sensitivity from water vapour where the water vapour could quench the excited specie that is responsible for luminescence.…”

Section: Introductionmentioning

confidence: 99%

Sources of uncertainty in eddy covariance ozone flux measurements made by dry chemiluminescence fast response analysers

et al. 2010

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Abstract. We present a systematic intercomparison study of eddy covariance ozone flux measurements made using two fast response dry chemiluminescence analysers. Ozone deposition was measured over a well characterised managed grassland near Edinburgh, Scotland, during August 2007. A data quality control procedure specific to these analysers is introduced. Absolute ozone fluxes were calculated based on the relative signals of the dry chemiluminescence analysers using three different methods and the results are compared for both analysers. It is shown that the error in the fitted analyser calibration parameters required for the flux calculations provides a substantial source of uncertainty in the fluxes. The choice of the calculation method itself can also constitute an uncertainty in the flux as the calculated fluxes by the three methods do not agree within error at all times. This finding highlights the need for a consistent and rigorous approach for comparable datasets, such as e.g. in flux networks. Ozone fluxes calculated by one of the methods were then used to compare the two analysers in more detail. This systematic analyser comparison reveals half-hourly flux values differing by up to a factor of two at times with the difference in mean hourly flux ranging from 0 to 23% with an error in the mean daily flux of ± 12%. The comparison of analysers shows that the agreement in fluxes is excellent for some days but that there is an underlying uncertainty as a result of variable analyser performance and/or non-linear sensitivity.

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“…The thermostated head 3 with the chemiluminescent disc (25 ram) is mounted 10 mm in front of a cheap side-window photomultiplier 2 by a bayonet fitting so that the chemiluminescent disc can easily be replaced. Contrary to Regener's prototype ozone analyzer (Regener, 1964) and Hodgeson's improved version (Hodgeson et al, 1970), which used expensive red sensitive photomultipliers, our novel sensor operates with a cheap blue sensitive photomultiplier (Hamamatsu 931B) which is most sensitive in the 400 to 500 nm spectral range. Among the many dyes tested in the chemiluminescence reaction with ozone (Bowman and Alexander, 1966;Hill et al, 1982) we favoured coumarin dyes emitting in the blue spectral range, in particular coumarin-47 (Sahand et al, 1987).…”

Section: Methodsmentioning

confidence: 99%

“…Among the many dyes tested in the chemiluminescence reaction with ozone (Bowman and Alexander, 1966;Hill et al, 1982) we favoured coumarin dyes emitting in the blue spectral range, in particular coumarin-47 (Sahand et al, 1987). Several techniques for preparing dye-coated chemiluminescent surfaces have been described in the literature (Bowman et Alexander, 1966;Hodgeson et al, 1970;Hill et al, 1982;Sahand et al, 1987). In our sensor chemiluminescent discs are used which are prepared by the method of Speuser et al (Speuser et al, 1989).…”

Section: Methodsmentioning

confidence: 99%

A novel ozone sensor for direct eddy flux measurements

et al. 1992

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Asmall, lightweight (1.5 kg) and fast-response ozone sensor for direct eddy flux measurements has been built. The basis for detection is the chemiluminescence of an organic dye adsorbed on dry silica gel in the reaction with ozone. The chemiluminescence is monitored with a cheap and small blue-sensitive photomultiplier. At a flow rate of 100 I min d the ozone sensor has a 90 % response time of significantly better than 0.1 s with a detection limit lower than 50 ppt at SIN = 3. There are no interferences from other atmospheric trace gases like NOx, H202 and PAN. Water vapour and SO2 enhance the chemiluminescence efficiency of the ozone sensor. Since their response times are 22 seconds and 30 minutes, respectively, no correlation between rapid ozone fluctuations and those of these two trace gases is noticed by the ozone sensor when operating at a frequency of 10 Hz.The ozone sensor was tested for several weeks in continuous measurements of ozone fluxes and deposition velocities over different croplands using the eddy correlation technique Good agreement was found between ozone dry deposition velocities derived from profile measurements and by eddy correlation.

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Chemiluminescent measurement of atmospheric ozone. Response characteristics and operating variables

Cited by 54 publications

References 13 publications

Detection of Organic Molecules Dissolved in Water Using a γ-Al2O3 Chemiluminescence-Based Sensor

Detection of Organic Molecules Dissolved in Water Using a γ-Al2O3 Chemiluminescence-Based Sensor

Sources of uncertainty in eddy covariance ozone flux measurements made by dry chemiluminescence fast response analysers

A novel ozone sensor for direct eddy flux measurements

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