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Temperature and humidity compensation in the determination of solvent vapors with a microsensor system.

Authors
Park-J; Zellers-ET
Source
Analyst 2000 Oct; 125(10):1775-1782
NIOSHTIC No.
20029861
Abstract
Accounting for changes in temperature and ambient humidity is critical to the development of practical field vapor-monitoring instrumentation employing microfabricated sensor arrays. In this study, responses to six organic vapors were collected from two prototype field instruments over a range of ambient temperatures and relative humidities (RH). Each instrument contains an array of three unthermostated polymer-coated surface acoustic wave (SAW) resonators, a thermally desorbed adsorbent preconcentrator bed, a reversible pump and a small scrubber cartridge. Negligible changes in the vapor sensitivities with atmospheric RH were observed owing, in large part, to the temporal separation of co-adsorbed water from the organic vapor analytes upon thermal desorption of preconcentrated air samples. As a result, calibrations performed at one RH level could be used to determine vapors at any other RH without corrections using standard pattern recognition methods. Negative exponential temperature dependences that agreed reasonably well with those predicted from theory were observed for many of the vapor-sensor combinations. It was possible to select a subset of sensors with structurally diverse polymer coatings whose sensitivities to all six test vapors and selected binary vapor mixtures had similar temperature dependences. Thus, vapor recognition could be rendered independent of temperature and vapor quantification could be corrected for temperature with sufficient accuracy for most applications. The results indicate that active temperature control is not necessary and that temperature and RH compensation is achievable with a relatively simple microsensor system.
Keywords
Organic-vapors; Detectors; Analytical-instruments; Acoustic-signals; Solvent-vapors; Solvents; Humidity
Contact
Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 4801-2029
CODEN
ANALAO
CAS No.
127-18-4; 79-01-6; 76-38-0
Publication Date
20001001
Document Type
Journal Article
Funding Amount
310921
Funding Type
Grant
Fiscal Year
2001
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-03332
Issue of Publication
10
ISSN
0003-2654
Priority Area
Grants-other
Source Name
Analyst
State
ME; MI
Performing Organization
University of Michigan at Ann Arbor, Ann Arbor, Michigan
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