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.
The Unregulated Contaminant Monitoring Program (UCMR3) recently announced a new rule that requires public drinking water facilities to collect data on roughly 30 contaminants from January 2013 through December 2015. For the VOC portion of this rule, seven (down from the original nine) were selected for analysis by US EPA Method 524.3, using selective ion monitoring (SIM) to reach MRLs as low as 0.03 µg/L.