Online Reference Calibration for Electrochemical Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrochemical sensors face instability issues with reference electrodes, requiring frequent recalibration and manual intervention, which limits their use in autonomous and networked systems due to drifts in reference potential caused by changes in chloride ion concentration and solution chemistry.
Innovation Solution
An online calibration system using a calibration electrode with a redox species sensitive to pH, which sets the local pH of the reference solution and generates a constant peak potential, allowing for independent calibration of the reference potential without manual intervention, even in conditions of dilution or contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reference electrode is used in electrochemical sensors, then the reference potential can be maintained, but drift in reference potential occurs due to changes in chloride ion concentration and solution chemistry
Solution Approach 1:
A calibration electrode containing a redox species acts as an intermediary between the reference electrode and the test solution. This calibration electrode generates a stable, known potential that is independent of chloride ion concentration, thereby mediating the reference potential measurement and eliminating the drift caused by solution chemistry changes.
Solution Approach 2:
The invention changes the measurement parameter from direct reference potential measurement to measurement of the difference between calibration electrode potential and reference electrode potential. This parameter transformation allows the system to compensate for reference electrode drift by repeatedly measuring and correcting the potential difference.
2Measurement precision
If manual recalibration is performed frequently, then reference potential accuracy is maintained, but system autonomy is reduced and maintenance requirements increase
Solution Approach 1:
The calibration electrode enables the system to perform self-calibration by automatically measuring the potential difference between the calibration electrode and reference electrode, and using this measurement to correct reference potential drift. This eliminates the need for manual recalibration and maintains system autonomy.
Solution Approach 2:
The system implements feedback by repeatedly measuring the potential difference between the calibration electrode and reference electrode during operation. This continuous feedback allows the system to detect and correct reference potential drift in real-time, maintaining accuracy without manual intervention.
3Duration of action of moving object
If the reference solution is diluted or contaminated during use, then the sensor can operate continuously, but the reference electrode potential drifts
Solution Approach 1:
The calibration electrode is pre-filled with a redox species that establishes a stable, known potential independent of the reference solution composition. This preliminary preparation allows the electrode to maintain its calibration function even when the reference solution becomes diluted or contaminated during continuous operation.
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 system provides stable and accurate calibration of the reference potential, reducing maintenance requirements and enabling long-duration, autonomous operation of electrochemical sensors by correcting drifts in the reference electrode potential, regardless of changes in chloride ion concentration or solution chemistry.
Implementation Method 1
The calibration electrode comprises a redox species that is sensitive to pH/hydrogen ion concentration and is configured to set a pH of the reference solution local to the calibration electrode, such that when an electrochemical/voltammetric signal is applied to the calibration electrode, the calibration electrode generates an electrochemical/voltammetric response that has a constant feature
Data Source
AI summary
An online calibration system for an electrochemical sensor. The calibration system comprises a calibration electrode coupled with a redox species, where the redox species is configured to control a pH of a reference solution local to the calibration electrode, such that when a voltammetric signal is applied to the calibration electrode the output generated from the calibration system is determined by the local environment pH. The output signal from the calibration system is used to calibrate a reference potential generated by a reference system of the electrochemical sensor to correct for drift in the reference potential when the electrochemical sensor is being used. The calibration electrode may be disposed in a reference cell of the electrochemical sensor.