Determination of air-to-water partition coefficients using automated multiple headspace extractions

Air-to-water partition coefficients are experimentally determined using a multiple headspace extraction procedure and an automated headspace cell. The approach is first validated with 2-butanone and then applied to a homologous series of methyl ketones. As adsorptions of the most hydrophobic compounds occurred in the sampling cell, technical improvements have been tested. This study represents the first attempt to overcome analyte adsorptions by studying and minimizing the effect of the cell's adsorption of hydrophobic analytes on the determination of their partition coefficients. The present method allows the measurement of several analytes at the same time, in the ppm range, without calibration, and with a limited manpower.