Measurement of Henry's law constant for methyl tert-butyl ether using solid-phase microextraction

Increasing groundwater contamination with methyl tert-butyl ether (MTBE) re quires more efficient remediation technologies. Accurate measurement of MTB E's air-water partitioning coefficient (Henry's law constant, H) is importa nt for the design and optimization of removal efficiency for many treatment systems as well as;for predicting its fate and transport. Previously publi shed data for MTBE appear to have some unusual nonlinearity at lower temper atures (15-30 degreesC), and a wide range of values exists for dimensionles s H at 25 degreesC, from 0.0216 to 0.1226 in the published literature. We m easured H for MTBE using headspace solid-phase microextraction (SPME) and a static method that considers equilibrium partitioning in a closed system; f or temperatures between 15 and 40 degreesC. To validate our methods, we mea sured H for benzene, toluene, and trichloroethylene and compared our result s to previously published values, with excellent agreement. The Arrhenius p lot for MTBE indicates that ln(H-MBTE) = 6.85 - 2,900 T-1, with T in K. At 25 degreesC, H-MBTE = 0.0555 +/- 0.0122.