Part of developing new and relevant applications is staying on top of current events, which can mean reading through a lot of news articles. The one topic we run into most often, especially recently here in Ohio, is hydraulic fracturing. Recently, the governor of Ohio announced increased fees for dumping wastewaters associated with hydraulic fracturing from out of state sources. All implications are that these drilling activities will have a national as well as global impact, as evident by this map of the shale gas plays in North America.
Figure 1: Shale Gas Formations in North America
One major concern with the increase in these drilling activities is the environmental impact of the chemicals used by these drilling companies. Along with the increased drilling also comes the worry of methane migrating into drinking water supplies. Baseline and long term testing has become standard it many states as a way to keep the drilling companies accountable. This also helps establish any preexisting methane background in the local drinking water, which can be considerable in some shale-rich areas. The most common method used for analyzing these drinking water samples for methane is the EPA SOP RSK 175, a manual headspace method.
Tekmar has been at the forefront of these dissolved gas applications. An RSK 175 application note has been available for a few years for our HT3 headspace sampler to automate this analysis. With the rapid growth of hydraulic fracturing, interest has also increased in the potential environmental impacts and the need for accurate and efficient testing methods. We took this opportunity to revisit and modify our dissolved gas applications (Two Headspace Solutions for the Analysis of Dissolved Gases in Water by Method RSKSOP-175) as well as develop a purge and trap method (An Alternative Method to RSK 175 using a Purge and Trap Concentrator and GC/FID), employing a proprietary trap developed for this analysis. These improved methods enable quicker analysis times and less sample handling than standard manual methods. Using a GC/FID and the appropriate column, this is a fairly straight forward separation that allows for some very quick GC cycles with some additional method optimization. An example chromatogram for gas standards run on a GC/FID can be found in Figure 2.
Figure 2: Overlay Chromatograms of Gas Standards using the Purge and Trap method
In addition to the application notes already available, we will be presenting a poster on modified methods for dissolved gas analysis (both headspace and P&T) at the National Environmental Monitoring Conference (NEMC) in Washington, DC next week. Feel free to stop by the poster session or contact us with any questions you might have on setting up for this analysis.