Field intercomparison of a novel optical sensor for formaldehyde quantification

Friedfeld, Stephen; Fraser, Matthew P.; Lancaster, David G.; Leleux, D.; Rehle, D.; Tittel, Frank K.

doi:10.1029/2000gl011523

Cited by 33 publications

(10 citation statements)

References 16 publications

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“…Clearly, this procedure is unable to provide formaldehyde exposure information on a realtime basis. Hence, a number of researchers have developed optical sensors for formaldehyde quantification applications [7][8][9][10]. However, the associated optical arrangements tend to be rather bulky and elaborate.…”

Section: Introductionmentioning

confidence: 99%

A self-heating gas sensor with integrated NiO thin-film for formaldehyde detection

Lee

Chiang

Wang

et al. 2007

Sensors and Actuators B: Chemical

246

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Section: Introductionmentioning

confidence: 99%

A self-heating gas sensor with integrated NiO thin-film for formaldehyde detection

Lee

Chiang

Wang

et al. 2007

Sensors and Actuators B: Chemical

246

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“…In situ spectroscopic methods (e.g., long-path Fourier-transform infrared absorption spectroscopy, differential optical absorption spectroscopy, tunable diode laser absorption spectroscopy, laser-induced fluorescence spectroscopy, and laser absorption spectroscopy based on difference frequency generation) have been reported and compared for measurement of formaldehyde concentration in real or near-real time. [25][26][27][28] The best of these are well suited as reference techniques, but routine application is deterred by their size, cost, and the need for an expert operator.…”

Section: Introductionmentioning

confidence: 99%

Measurement of atmospheric formaldehyde with a diffusion scrubber and light‐emitting diode–liquid‐core waveguide based fluorometry

Dasgupta

Zhang

et al. 2001

Field Analytical Chem & Tech

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A new automated instrument for the near-realtime measurement of atmospheric formaldehyde is described. The chemistry involves the cyclization reaction of formaldehyde with 1,3-cyclohexanedione (CHD) in the presence of ammonium ions to form a fluorescent dihydropyridine derivative. A GaN-based light-emitting diode (LED) emitting in the near UV was used as the excitation source in a miniature flowthrough fluorescence detector based on a transversely illuminated liquid-core waveguide. The instrument is configured to operate in a periodic autozero mode where the exhaust from the sampling pump is chemically treated to provide zero gas for automated periodic checks of the baseline. The liquidphase portion of the system provides a S/N ‫؍‬ 3 limit of detection (LOD) of 10-nM aqueous formaldehyde. A thermostated Nafionா-membrane-based diffusion scrubber is used to collect atmospheric formaldehyde into pure water with an absorption efficiency of ϳ70%, which results in an LOD of 30 pptv HCHO. (In cases where the H 2 O 2 to HCHO ratio is very high, as in background polar atmospheres, the LOD will deteriorate markedly.) Design, performance details, and illustrative results from a 1999 field campaign (Atlanta Supersite Study) are presented. Interference from H 2 O 2 is discussed in detail.

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“…This procedure is clearly incapable of providing immediate formaldehyde exposure information. Hence, several researchers have developed optical sensors for formaldehyde quantification applications (Mine et al 1997;Friedfeld and Fraser 2000). However, the associated optical arrangements are bulky and elaborate.…”

Section: Introductionmentioning

confidence: 99%

MEMS-based formaldehyde gas sensor integrated with a micro-hotplate

et al. 2006

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This paper presents a novel micro-fabricated formaldehyde gas sensor with enhanced sensitivity and detection resolution capabilities. The device comprises a quartz substrate with Pt heaters as a micro-hotplate and deposited formaldehyde-sensing layer on it. A sputtered NiO thin film is used as the formaldehyde-sensing layer. A specific orientation of NiO becomes more apparent as the substrate temperature increases in the sputtering process, which helps the formation of NiO material with a correct stoichiometric ratio. The gas sensor incorporates Pt heating resistors integrated with a micro-hotplate to provide a heating function and utilizes Au inter-digitated electrodes. When formaldehyde is present in the atmosphere, oxydation happens near the sensing layer with a high temperature caused by the micro-hotplate and causes a change in the electrical conductivity of the NiO film. Therefore, the measured resistance between the inter-digitated electrodes changes correspondingly. The application of a voltage to the Pt heaters causes the temperature of the micro-hotplate to increase, which in turn enhances the sensitivity of the sensor. The nanometer scale grain size of the sputtered oxide thin film is conducive to improving the sensitivity of the gas sensor. The experimental results indicate that the developed device has a high stability (0.23%), a low hysteresis value (0.18%), a quick response time (13.0 s), a high degree of sensitivity (0.14 X ppm À1 ), and a detection capability of less than 1.2 ppm.

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Field intercomparison of a novel optical sensor for formaldehyde quantification

Abstract: Abstract.A one-week in situ intercomparison campaign was completed on the Rice University campus for measuring HCHO using three different techniques, including a novel op-

Cited by 33 publications

References 16 publications

A self-heating gas sensor with integrated NiO thin-film for formaldehyde detection

A self-heating gas sensor with integrated NiO thin-film for formaldehyde detection

Measurement of atmospheric formaldehyde with a diffusion scrubber and light‐emitting diode–liquid‐core waveguide based fluorometry

MEMS-based formaldehyde gas sensor integrated with a micro-hotplate

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