Steric factors affecting the discrimination of isomeric and structurally related olefin gases and vapors with a reagent-coated surface acoustic wave sensor.
Anal Chem 1992 Jun; 64(11):1277-1284
The extent to which steric factors could be exploited to obtain selectivity for unhindered olefins in the presence of hindered olefins with these reagents coated on a surface acoustic wave (SAW) sensor was determined. Detection was based on the mass increase accompanying replacement of ethylene by other gas phase olefins to form the corresponding olefin substituted products. Selectivity depended on the relative reaction rates of the different olefins. Unusually high selectivity was observed for the less hindered olefins and complete discrimination of isomers was achieved in certain cases. The sensor response was progressively reduced by replacing pyridine by 2-methylpyridine and 2,6-dimethylpyridine in the reagent complex. With increasing temperature the sensitivities increased. The limits of detection ranged from 2 to 70 micrograms/liter and were achieved with modest heating of 30 to 40 degrees-C using a 30 megahertz SAW oscillator. Initial results with a 52 megahertz sensor showed a 3.4 fold increase in sensitivity compared to the 30 megahertz sensor, in rough agreement with theory.
NIOSH-Publication; NIOSH-Grant; Grants-other; Analytical-methods; Chemical-analysis; Analytical-chemistry; Temperature-effects; Air-quality-monitoring
Environmental & Indust Health University of Michigan Dept of Environmental Hlth Ann Arbor, MI 48109-2029
Other Occupational Concerns; Grants-other
University of Michigan at Ann Arbor, Ann Arbor, Michigan