SPRAY EXTRACTION OF VOLATILE ORGANIC-COMPOUNDS FROM AQUEOUS SYSTEMS INTO THE GAS-PHASE FOR GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

A new sampling technique has been developed for extracting volatile organic compounds from aqueous solutions. Using a spray nozzle, very small droplets of the aqueous solution are generated in an extraction chamber. The so-obtained large total interface area between the liquid and gas phase helps to quickly reach the partition equilibrium of dissolved compounds between the liquid and the gas phase. Substances extracted into the gas phase are preconcentrated in a sorption tube gas-sampling device. A thermal desorption following the preconcentration allows the collected compounds to enter the gas chromatographic column of the GCMS. The spray-and-trap method is very sensitive and can be applied to sampling of very low concentrations (down to 10-30 ng/L with 2 min of sampling). The spray extractor has the capability of operating with aqueous systems containing surfactants.