Electrochemical sensor for lead detection
Inventors
Akolkar, Rohan • Liu, Xinyu • Venkatraman, Kailash
Assignees
Case Western Reserve University
Publication Number
US-12241862-B2
Publication Date
2025-03-04
Expiration Date
2039-01-23
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Abstract
A sensor for detecting lead in an aqueous solution includes a copper working electrode, a counter electrode, a power supply for applying underpotential deposition of lead onto the copper electrode, a measuring device for providing measurement of a hydrogen evolution reaction (HER) current on the Pbupd-modified electrode, and a controller configured to correlate the degree of suppression of the HER current to Pbupd coverage to determine the lead coverage and lead concentration of the solution.
Core Innovation
The invention addresses the need for a low-cost, portable, and reliable sensor to detect lead in aqueous solutions, such as drinking water, where conventional techniques like colorimetry, atomic absorption spectroscopy, and ICP emission spectroscopy are expensive and limited to certified laboratories. The problem is the presence of lead contamination in water, often from distribution systems like lead pipes, requiring detection at levels as low as parts per billion (ppb) to comply with regulatory standards.
The core innovation is an electrochemical sensor that detects, identifies, and quantifies lead in an aqueous solution by using a copper working electrode and a counter electrode. The sensor operates by applying an underpotential deposition (UPD) of lead onto the copper electrode and then measuring the hydrogen evolution reaction (HER) current on the lead-modified copper electrode. The suppression of the HER current, correlated to the amount of deposited lead, is used to determine the lead coverage and lead concentration in the solution.
The system can be implemented with electrodes formed via techniques like film printing or sputtering, optionally using laser ablation for precise definition and reduced measurement variability. Some embodiments feature a copper working electrode with a needle-like dendritic surface profile, produced via zinc dendrite potentiostatic plating and subsequent copper electroplating. This dendritic structure reduces sensing time compared to planar surfaces. The sensor may be incorporated into a chip-based or handheld device, providing automated detection and quantitative output of lead concentration based on the measured suppression of the HER current.
Claims Coverage
The patent includes one independent claim detailing five main inventive features of the described sensor.
Copper working electrode for lead detection
The sensor includes a copper working electrode that is specifically intended for placement in an aqueous solution to serve as the active element for the underpotential deposition (Pbupd) of lead.
Counter electrode in aqueous solution
A counter electrode is configured to be placed in the aqueous solution along with the copper working electrode, enabling the required electrochemical reactions.
Power supply for underpotential deposition
The sensor utilizes a power supply designed to apply an underpotential deposition specifically for lead (Pbupd) onto the copper working electrode, which is critical for subsequent detection steps.
Measuring device for hydrogen evolution reaction current
A measuring device is provided to measure the hydrogen evolution reaction (HER) current on the Pbupd-modified copper electrode, serving as the basis for detecting the presence and quantity of lead.
Controller for correlating HER current suppression to lead concentration
The sensor includes a controller configured to correlate the degree of suppression of the HER current to the Pbupd coverage, thereby determining both lead coverage and lead concentration in the solution.
The independent claim covers a sensor designed for detecting lead in aqueous solutions using a combination of a copper working electrode, a counter electrode, precise underpotential deposition, HER current measurement, and a controller for data interpretation.
Stated Advantages
The sensor enables detection of ppb-levels of Pb2+ in water.
Provides a low-cost, portable, and reliable method for lead detection compared to conventional laboratory-based techniques.
The sensor can function without electrolyte de-aeration, allowing operation in real-world aqueous environments.
Copper working electrodes with needle-like dendrite surface profile decrease lead sensing time compared to planar surfaces.
Measurement method is not significantly affected by competing electrochemical reactions or background currents.
Documented Applications
Detection, identification, quantification, and determination of the amount or level of lead in drinking water, tap water, or other aqueous fluids.
Use in homes and offices for on-site lead detection in water supplies.
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