Polymer-Coated Redox pH Electrode for Low-Buffer Accuracy
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Solution Overview
Problem
Existing electrochemical sensors face inaccuracies in measuring pH in low buffering capacity solutions due to erroneous surface functionalizations of carbon-based materials, which perturb the local pH, and require additional sensors or calibration in seawater due to ionic strength differences.
Innovation Solution
A composite working electrode with a redox active species configured for hydrogen bonding through a carbon ring, encapsulated in a polymer coating, such as polysulfone, to stabilize and enhance the electrochemical response in low buffering capacity solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carbon-based materials are used as working electrode, then electrochemical response is enhanced, but erroneous surface functionalizations perturb the local pH and cause measurement inaccuracy
Solution Approach 1:
The patent removes the harmful surface functionalizations (carboxyl, hydroxyl, carbonyl groups) from the carbon-based material surface through controlled oxidation treatment, extracting only the erroneous functional groups while preserving the beneficial carbon structure for electrochemical response
Solution Approach 2:
The patent converts the harmful erroneous surface functionalizations into beneficial controlled oxidation products by using controlled oxidation treatment, transforming the problematic carboxyl/hydroxyl/carbonyl groups into a controlled oxidation state that provides stable electrochemical response without local pH perturbation
2Reliability
If glass electrode is used for pH measurement, then measurement is reliable, but the electrode is fragile and requires regular calibration and special storage conditions
Solution Approach 1:
The patent replaces the mechanical glass electrode system with an electrochemical sensor based on redox-active species that provide pH response through electrochemical reactions, eliminating the need for mechanical glass structure and its associated fragility and calibration requirements
Solution Approach 2:
The patent changes the measurement mechanism from potentiometric (glass electrode potential) to electrochemical (redox couple potential), transforming the measurement principle to enable direct pH sensing without calibration, utilizing the Nernstian response of the redox couple to pH changes
3Ease of operation
If classical quinone/hydroquinone voltammetry is used to monitor pH, then the method is simple, but the proton coupled electrochemical process perturbs the pH of the solution locally
Solution Approach 1:
The patent introduces an intermediary substance (redox-active species with appropriate redox potential) that mediates the pH sensing process, enabling pH measurement through electrochemical reactions without direct proton coupling that would cause local pH perturbation
Solution Approach 2:
The patent changes the electrochemical mechanism from proton-coupled electron transfer to a redox process where the redox potential of the couple depends on pH according to the Nernst equation, allowing pH measurement without local pH change during the measurement process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The electrode provides accurate and reproducible pH measurements in low buffering capacity solutions, including water and seawater, by minimizing perturbation and enhancing hydrogen bonding, resulting in a stable and defined output.
Implementation Method 1
an electrochemical sensor comprising a working electrode for electrochemical pH sensing using a chemistry/redox active species configured to provide for hydrogen bonding with a moiety fixed in a carbon ring
Implementation Method 2
a redox active species configured to provide for hydrogen bonding with a moiety fixed in a carbon ring
Data Source
AI summary
A composite working electrode comprising at least one polysulfone coated carbon material and at least one active redox species comprising an oxygen family atom bound in a ring structure, wherein the ring structure is substituted with a carbon ring, and wherein a moiety containing a hydrogen atom is attached to the carbon ring such that it is configured to provide for hydrogen bonding with the bound oxygen family atom and an electrochemical sensor comprising said composite working electrode.