2026 Student Poster Presentation Competition
WQRF and Pentair Water Solutions are hosting current undergraduate and postgraduate students interested in drinking water to participate in a competitive call for posters. Posters will be displayed at the annual Water Quality Association's (WQA) Convention + Expo in Miami, Florida, on April 29 and 30, 2026.
Abstract Submission:
Engineering Novel Janus Gold Nanorods as a Platform for Smartphone-based Lead Detection
Abstract Submission:
Engineering Novel Janus Gold Nanorods as a Platform for Smartphone-based Lead Detection
John Gorman, Ben Hein, and Haoran Wei | University of Wisconsin-Madison
While there is no safe limit for lead in water, the EPA sets an action level at 10 ppb. Unfortunately, exceedances are common in states with a high number of remaining lead service lines. While at-home lead tests exist, they are often unreliable, highly subjective, or have poor limits of detection. The goal of this project is to develop an inexpensive and simple smartphone-based lead sensor based on thiosulfate leaching of novel gold Janus nanorods (AuJNR). AuJNR hold many unique optical properties stemming from their delocalized electron cloud, size, and shape, including an unusually strong absorbance peak at around 850 nm. The exact absorbance wavelength and intensity shift linearly with a change in the length of the AuJNR; the length, in turn, can be controlled via chemical leaching using combination of thiosulfate and 2-mercaptoethanol. Critically, lead predictably catalyzes this reaction, meaning it can be used to quantify the concentration of lead in water. Initial testing indicates that this technique can quantify lead down to the 2.5 ppb level, well below the EPA’s action level for remediation. Moreover, low-cost smartphone apps already exist to monitor absorbance spectra and when used in combination with this novel AuJNR sensor, can provide a far superior at-home analysis compared to test strips. Further, this rapid, inexpensive, and simple testing will allow for better spatiotemporal testing for large scale lead analysis, particularly in low socioeconomic areas that are most in need of lead analysis. Such studies can both serve to enrich the scientific community by providing long-term data on water quality changes while also supporting community water monitoring efforts in the short term and bolstering support for regulatory change to keep people safe.
While there is no safe limit for lead in water, the EPA sets an action level at 10 ppb. Unfortunately, exceedances are common in states with a high number of remaining lead service lines. While at-home lead tests exist, they are often unreliable, highly subjective, or have poor limits of detection. The goal of this project is to develop an inexpensive and simple smartphone-based lead sensor based on thiosulfate leaching of novel gold Janus nanorods (AuJNR). AuJNR hold many unique optical properties stemming from their delocalized electron cloud, size, and shape, including an unusually strong absorbance peak at around 850 nm. The exact absorbance wavelength and intensity shift linearly with a change in the length of the AuJNR; the length, in turn, can be controlled via chemical leaching using combination of thiosulfate and 2-mercaptoethanol. Critically, lead predictably catalyzes this reaction, meaning it can be used to quantify the concentration of lead in water. Initial testing indicates that this technique can quantify lead down to the 2.5 ppb level, well below the EPA’s action level for remediation. Moreover, low-cost smartphone apps already exist to monitor absorbance spectra and when used in combination with this novel AuJNR sensor, can provide a far superior at-home analysis compared to test strips. Further, this rapid, inexpensive, and simple testing will allow for better spatiotemporal testing for large scale lead analysis, particularly in low socioeconomic areas that are most in need of lead analysis. Such studies can both serve to enrich the scientific community by providing long-term data on water quality changes while also supporting community water monitoring efforts in the short term and bolstering support for regulatory change to keep people safe.