Measurement of aqueous Henry's law constants for oxygenates and aromatics found in gasolines by the static headspace method

A simple equilibrium vessel made from a large stopcock was used in conjunct ion with the static headspace method to measure the aqueous Henry's law con stants for methyl tert-butyl ether (MTBE) and other potential oxygenates as well as certain of the aromatics found in gasoline. The present method inv olves using only one aqueous solution whose concentration is not necessaril y known. The only quantity that must be known is the phase ratio. Plotting a series of peak areas of the analyte in the headspace after each equilibri um change against the initial peak area of the analyte found in the headspa ce leads to a linear relationship whose slope is dependent on the analyte's unitless Henry's law constant and the phase ratio. This new method is foun d to yield unitless aqueous Henry's law constants in the range from 0.02 to 0.2, which are especially applicable to the oxygenates and aromatics found in gasolines.