Drift Compensated Ion Sensor Using Dual Electrode Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Miniaturized ion sensors face challenges in maintaining stable reference electrode voltages due to chloride ion concentration changes, which are exacerbated by their small volume, limiting their application in environments where conventional reference electrodes are too large and rigid.
Innovation Solution
Incorporating a second ion-selective electrode in direct contact with the bulk solution to measure and compensate for the drift of the reference electrode voltage, allowing for stabilization without increasing the volume of the reference electrolyte solution, and using a hydrogel and barrier layer to prevent mixing with the bulk solution while maintaining ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the volume of the reference electrolyte solution is increased to stabilize the reference voltage, then the reference electrode potential stability is improved, but the device size increases and is no longer suitable for miniaturized applications
Solution Approach 1:
The patent implements a feedback mechanism by introducing a second reference electrode that continuously monitors the reference potential. When drift is detected, the system automatically compensates by adjusting the measurement to account for the drift, thereby maintaining measurement accuracy without requiring a large electrolyte volume.
Solution Approach 2:
The patent introduces a second reference electrode as an intermediary element that indirectly measures the drift of the first reference electrode. This intermediary electrode allows the system to detect and compensate for potential instability without requiring the main reference electrode to have a large volume.
2Volume of moving object
If miniaturized reference electrodes are used to reduce device size, then the device complexity is reduced and portability is improved, but the reference electrode drift increases due to small electrolyte volume
Solution Approach 1:
The patent employs a feedback-based drift compensation system where a second reference electrode monitors the potential stability of the first reference electrode. The measured drift is fed back to the measurement system, which automatically corrects for the drift, thereby maintaining measurement reliability in miniaturized sensors with small electrolyte volumes.
Solution Approach 2:
A second reference electrode is introduced as an intermediary monitoring element that does not participate directly in the measurement but provides information about reference electrode drift. This intermediary allows miniaturized sensors to maintain stability by enabling real-time drift detection and compensation.
3Reliability
If a porous frit is used to separate the reference electrolyte from the bulk solution, then ion migration is reduced and reference potential stability is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of relying solely on physical barriers like porous frits, the patent uses a feedback-based electrical compensation system. A second reference electrode monitors drift, and the system automatically corrects for it through signal processing, achieving reference potential stability through software/firmware rather than complex manufacturing.
Solution Approach 2:
The patent replaces the need for complex physical separation structures (porous frits) with an intermediary second reference electrode that electrically monitors and enables compensation for drift, simplifying the physical structure while maintaining reference potential stability through electronic/firmware-based correction.
4Manufacturing precision
If the reference electrode is made planar using photolithography for miniaturization, then the manufacturing precision is improved and mass production is enabled, but the reference electrolyte volume is reduced leading to increased drift
Solution Approach 1:
The patent maintains the advantages of planar photolithography fabrication while compensating for the drift caused by small electrolyte volume through a feedback mechanism. A second reference electrode monitors the drift, and the measurement system automatically corrects for it, enabling mass production of miniaturized sensors without sacrificing reference potential stability.
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
This approach provides a stable and accurate ion sensor capable of compensating for reference electrode drift, enabling miniaturization suitable for applications like sweat patches, smart wound monitoring, and integration in diapers, while maintaining ion conductivity and preventing electrolyte mixing.
Implementation Method 1
The reference electrode is embedded in a reference electrolyte solution and the electrolyte solution induces a voltage on the reference electrode
Implementation Method 2
Potentiometric sensors are used for detecting chemical or biochemical compounds in a solution. Such potentiometric sensors are electrochemical sensors that generate voltages that scale with the concentration of an ion to be determined.
Implementation Method 3
The potential difference between the ion-selective electrode and the reference electrode is a measure for the concentration of the compound for which the ion-selective electrode is sensitive.
Implementation Method 4
If the reference electrode is immersed in a solution with a different chloride concentration, chloride ions will leach out which leads to a change in chloride concentration in the reservoir
Implementation Method 5
This electrode has a fixed potential when in contact with a reservoir with a fixed chloride concentration, such as 3 Molar KCl (3M KCl).
Data Source
AI summary
An ion sensor for sensing an ion concentration in a bulk solution comprises a reference electrode embedded in an reference electrolyte solution, and a first ion-selective electrode. The ion sensor moreover comprises a second electrode sensitive to the reference ions or to an ion different from the ion to be measured, whereby the second electrode is in direct contact with the bulk solution when the ion sensor is immersed therein. The potential difference between the first electrode and the reference electrode is a measure for the ion concentration in the bulk solution and is corrected with the potential difference between the second electrode and the reference electrode to compensate for the drift of the reference electrode.