Gas Chromatographic Determination of Low Concentrations of Hydrocarbons in Water by Vapor Phase Extraction

A novel system for the measurement of low concentrations of hydrocarbons in water is described. The apparatus introduces a vapor sample of the hydrocarbon to a gas chromatograph following transfer of part of the hydrocarbon from the aqueous solution to a vapor phase. The thermodynamic basis for predicting the vapor-liquid equilibration is given. The method is capable of analyzing hydrocarbon concentrations in parts per billion range; however, the sensitivity depends on the hydrocarbon solubility and vapor pressure.