In-situ PFC Monitoring SensorsUnited Science
Chunze Lai, Ph.D.
Introduction: Our fluorous PFC sensors aim at monitoring perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) with no cost, at low concentration and in-situ.
Background: PFOA and PFOS are ubiquitous environmental contaminants that have been found at low concentrations in waste water, drinking water, human blood, and in food. Because PFOA, PFOS and other perfluorochemicals (PFCs) are bio-accumulative, extremely persistent and toxic, several states have established analytical methods and emission limits. Furthermore, there is a huge effort surrounding remediation of PFOA and PFOS contaminated areas. Considering the impacts on both the environment and public health, it is important to monitor PFOA and PFOS. Although there are established LC/MS/MS methods to measure PFOA and PFOS at low levels, this equipment is expensive and not generally field portable.
Method: Our sensors take advantage of the highly selective and fouling-resistant fluorous membranes licensed from the University of Minnesota. Fluorous phase has extremely low polarity and is immiscible with either aqueous phase or organic phase, therefore, lowering the solvation of interferences in the membrane phase. Our fluorous PFC sensors exhibit nice Nernstian responses to both PFO– and PFOS– (a 59.2 mV increase in potential for every ten-fold decrease in the PFO– or PFOS–concentration), and extremely high selectivities of 4.0 ×106 to 1 for PFO– and1.6×107 to 1 for PFOS– were obtained over Cl– with good stability in basic solution. Taking the benefit of the high selectivity from fluorous membrane and the elimination of transmembrane ion fluxes from solid-contact electrode setup, detection limits as low as 0.17 nM for PFO– and 0.86 nM forPFOS– have been received. These sensors are field and lab deployable, permit selective and fast measurement of PFOA and PFOS at low cost.
Applications: Our fluorous PFC sensors could be used in a wide variety of matrixes, including waste water, drinking water and wetlands. Ongoing research will expand the application of the electrode to measure the contaminant in blood, soil and food.