In gas phase analysis, water can be a big challenge. Like the analytes of interest, it is volatile. Generally in gas chromatography, water can be the enemy of just about every component of the GC, from the injector to the column to the detector. And when using a purge and trap concentrator for the sample preparation, the matrix is water, so dealing with it is unavoidable. Our task, then, is to try to decrease the amount of water and minimize the effects of water on the GC and the resulting chromatography.