Use of a surface-acoustic-wave sensor to characterize the reaction of styrene vapor with a square-planar organoplatinum complex.
Zellers-ET; White-RM; Rappaport-SM
Anal Chem 1990 Jul; 62(13):1222-1227
The reaction of styrene (100425) vapor with the square planar platinum-ethylene pi complex, trans-PtCl2(ethylene)pyridine was characterized using a coated surface acoustic wave (SAW) sensor. A dual SAW delay line oscillator configuration was used; one oscillator was coated with a solvent cast film of the solid platinum- ethylene complex dispersed in a poly(isobutylene) matrix, and the second oscillator was coated only with polymer. Absorbed styrene vapor displaced ethylene to form the stable styrene substituted complex trans-PtCl2(styrene)(pyridine), causing a decrease in the oscillator frequency from the increase of mass on the surface of the sensor. For short term exposure, there was a linear relationship between the logarithm of the rate of frequency change and the logarithm of the styrene vapor concentration consistent with a power law kinetic model for the heterogeneous trapping reaction. Deviation from the relationship above 300 parts per million (ppm) at 25 degrees-C was attributed to the onset of multilayer adsorption of styrene at the surface of the trapping reagent. The sensor response exhibited an Arrhenius temperature dependence permitting estimation of the thermal activation energy for the olefin substitution reaction. Calculated detection limits of three and 0.6ppm of styrene vapor were achieved for operation at 25 and 40 degrees-C, respectively. The authors conclude that the coated SAW sensor can serve as a useful probe of vapor solid reactions. The strong temperature dependence observed underscores the need for careful thermostating of the sensor during operation.
NIOSH-Publication; NIOSH-Grant; Analytical-chemistry; Chemical-analysis; Analytical-methods; Vapor-detectors; Organic-vapors; Physical-chemistry; Monitoring-systems; Chemical-kinetics; Analytical-instruments; Air-monitoring
Environmental & Indust Health University of Michigan Dept of Environmental Hlth Ann Arbor, MI 48109-2029
University of Michigan at Ann Arbor, Ann Arbor, Michigan