Principal Investigator

Tianhong Cui

Co-principal Investigators

Terrence Simon, Andy Erickson

Industry Partner

Nigel Pickering, Geosyntec Consulting


Increased levels of phosphate due to human activities often cause eutrophication and cyanobacteria growth. Accurate monitoring of phosphate is vital for water pollutant management. However, traditional measurement methods via spectrophotometry and colorimetry suffer from many drawbacks such as high analysis cost, long delay in analysis time, lack of on-site detection capability due to bulky equipment. A phosphate sensor that exhibits high sensitivity, high stability, high selectivity, low cost, and real-time detection capability is in high and immediate demand.


This project aims to develop an ultrasensitive and selective phosphate sensor based on a graphene field effect transistor that is capable of on-site and real-time measurement, offering facile fabrication, high sensitivity, and easy integration with existing electronics. A highly focused laser beam can induce local temperatures that are high enough to break chemical bonds of the carbon rich material and rearrange carbon atoms to form 3D porous graphene. The synthesis of the phosphate molecularly imprinted polymer membrane on top of graphene transistors is proposed to make the sensors only sensitive to phosphate with high specificity.


The research results from the proposed project will be distributed via presentations to multiple stakeholders including the scientific community and producers, extension services publications, and peer-reviewed publications in top-tier journals. Upon the completion of the project and in post-publication, the proposed phosphate sensor system will be patented and commercialized. The potential impact of low-cost, reliable, accurate, continuous, in situ sensors to measure phosphate cannot be overestimated. The implementation of low-cost, reliable, accurate, continuous, in situ sensors to measure phosphate could save Minnesotans (and beyond) tens of millions of dollars per year, thousands of hours in wet chemistry analysis and wait time, and produce more reliable and consistent data for assessment of our natural and engineered water systems.

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