A new, accurate, and experimentally simple method has been developed t
o determine dimensionless Henry's law constants using the static heads
pace method. The method appears applicable to a wide range of volatile
and semivolatile organic compounds. The method worked well even for m
ethyl tert-butyl ether (MTBE), despite its very high water solubility
and hence, low Henry's law constant. The approach developed extends th
e usefulness of the static headspace method in obtaining real-time, ac
curate information for assessing environmental problems.