Determination of trace organic impurities in water using thermal desorption from XAD resin.

A small water sample (20 to 250 ml) is passed through a small tube containing XAD-4 resin; this effectively retains the organic impurities present in the water. This tube is connected to the permanent apparatus and the sorbed organics are thermally transferred to a small Tenex pre-column while the water vapor is vented. The pre-column is closed off, preheated to 275--280 degrees C, and then a valve is opened to plug-inject the vaporized sample into a gas chromatography. The procedure works well for a variety of model organic compounds added to the water and can be used for the analysis of actual water samples.