Perfluorooctanoic acid (PFOA) is a ubiquitous environmental contaminant that has been found at low concentrations in waste water, drinking water, human blood, and in food. Because PFOA and other perfluorochemicals (PFCs) are bio-accumulative, extremely persistent, and toxic, the EPA has established analytical methods and preliminary health exposure and emission limits.  In addition to US regulatory efforts, the EU has renewed its drinking water PFOA directive testing mandate for 2011 and is continuing to gather toxicology data.  Furthermore, there are over 1000 groups actively researching PFOA related contamination in addition to industrial activity surrounding remediation of PFOA contaminated areas.  In response to this growing market need, we have created sensors for monitoring PFOA in drinking water and waste water.  Although there are established LC/MS/MS methods to measure PFOA at low levels in water matrices, this equipment is expensive and not field portable which greatly impedes research on the distribution and fate of these emerging environmental contaminants. This research aims at the development of a field and lab deployable ion-selective electrode that permits selective and fast measurement of PFOA with a low detection limit at low cost. The project will take advantage of the highly selective and fouling-resistant fluorous membranes recently licensed from the University of Minnesota.