Rapid, Sensitive Detection of PFOA with Smartphone-Based Flow Rate Analysis utilizing Competitive Molecular Interactions during Capillary Action

Case ID:

This invention pertains to a system of detecting perfluorinated-carbon alkyl chains (PFAs) with a smartphone by analyzing the flow rate. By using a paper-based microfluidic chip, this invention provides rapid detection of PFOAs in a lab. The procedure uses commonly available reagents to flow through a microfluidic chip while also loading it with the testing sample. Within 30 minutes of loading the sample, the scientist is able to gather their data. The readout time can be as low as five minutes. 

Perfluorinated-alkyl substances (PFAS) comprise around 10,000 different human-made agents that can be added to liquids to decrease surface tension with other solids, liquids, and gasses. They are commonly used in carpeting, upholstery, apparel, floor wax, textiles, firefighting foam, and sealants. PFAS are comprised of carbon chains linked to fluorine, resulting in the strongest polar covalent bond between carbon and another atom; a strong bond means they do not degrade quickly. These inert chemicals pose a potential risk to humans and their monitoring needs improvement. Perfluorooctanoic acid (PFOA), a specific type of PFAS, has been acknowledged as causing significant environmental damage to human health, being present in humans at a level of four parts per billion when 70 parts per trillion is considered the safe lifetime health advisory in drinking water by the EPA. 

Federal agencies are setting advisory levels of exposure and many state agencies are also enforcing regulations of limits on PFOA and PFAS contamination in drinking water. Current testing methods include high performance liquid chromatography, using methylene blue, or using a molecularly imprinted polymer (MIP). Using these types of detection requires training and can also be very expensive. Furthermore, the MIP process requires more investigation and the chromatography can take multiple days to return results. Chromatography does have the best limit of detection by analyzing lateral flow immunoassay on a paper-based microfluidic chip. 


  • PFAS/PFOA detection
  • Flow-rate analysis


  • Rapid
  • Inexpensive
  • Mobile
Patent Information:
Contact For More Information:
Tod McCauley
Assistant Director of Licensing, CALS
The University of Arizona
Lead Inventor(s):
Jeong-Yeol Yoon
Lane Breshears
Kelly Reynolds