Coated surface acoustic wave sensor employing a reversible mass-amplifying ligand substitution reaction for real-time measurement of 1,3-butadiene at low- and sub-ppm concentrations.
Anal Chem 1993 May; 65(10):1340-1349
The use of a surface acoustical wave (SAW) sensor for the real time measurement of low concentrations of butadiene (106990) gas was described. The SAW sensors tested were coated with several platinum (Pt) olefin complexes. After examining several different coatings, a effort was focused on the performance of trans-PtCl2-(1- hexene)(pyridine) and related complexes. Characterization of the trapping reaction, sensitivity and reproducibility of sensor responses, ability to regenerate the coating reagent, selectivity, humidity and temperature effects, sensor operating frequency, and the potential for real time monitoring of butadiene in the industrial environment were discussed. The displacement of two 1- hexene molecules by each butadiene molecule and the formation of the bridged complex brought about an amplification of the sensor response. A linear relationship was established between the rate of frequency change using a 30 megahertz (MHz) SAW oscillator and a butadiene air concentration ranging from 150 parts per billion (ppb) to 13 parts per million. A detection limit of 101ppb was obtained. This was further reduced to 24ppb by using a 60MHz oscillator. Changes in relative humidity from 5 to 80% caused no change in sensor response. Similarly a change in temperature from 25 to 35 degrees-C caused no change in sensor response. Several industrially relevant nonolefin compounds caused no interference. Interference was caused by several olefins. Brief exposure to 1-hexene vapor will regenerate the reagent.
NIOSH-Publication; NIOSH-Grant; Grants-other; Air-quality-monitoring; Butadienes; Measurement-equipment; Air-sampling; Industrial-gases; Organic-vapors
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