Electrochemical Sensor Admittance Ratio for Geometry Deviation Detection
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Solution Overview
Problem
Existing electrochemical sensor systems face challenges in reliably detecting deviations in the geometry of the detection zone and electrode surfaces, leading to incorrect measurements due to manufacturing errors, mechanical or thermal stress, and changes in the measurement conditions, which are not effectively addressed by current methods.
Innovation Solution
A method using alternating current to measure the conductivity between pairs of electrodes, forming a ratio of apparent conductance values to normalize and evaluate the electrochemically active surface area, allowing for the detection of deviations and prevention of incorrect measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actual measurement procedure is used as a control to detect sensor errors, then manufacturing errors and insufficient electrode coverage can be detected, but the detection time is delayed and identical errors in both channels are not detected
Solution Approach 1:
The invention applies a preliminary control measurement procedure before the actual measurement to detect sensor errors in advance. This preliminary check uses specific control measurements (such as measuring the same sample on both channels simultaneously or using reference measurements) to identify manufacturing errors, electrode coverage issues, or identical errors in both channels before they affect the actual diagnostic measurement, thereby enabling early detection without delaying the diagnostic process.
2Ease of manufacture
If adhesive or welding processes are used to bond plastic materials during test carrier production, then cost-effective manufacturing is achieved, but geometry deviations in the detection zone occur
Solution Approach 1:
The invention implements preliminary control measurements during or after the manufacturing process to detect geometry deviations in the detection zone before the test carriers are put into service. These control measurements verify that the adhesive or welding processes have not caused unacceptable geometry deviations, allowing for early identification and rejection of defective test carriers while maintaining cost-effective manufacturing processes.
3Ease of operation
If the measuring chamber is filled with sample liquid to enable measurement, then the electrochemical measurement can be performed, but changes in wetted surface area affect measurement accuracy
Solution Approach 1:
The invention compensates for changes in wetted surface area by using control measurements that are processed together with the actual measurement. The control measurements provide reference data that allows for mathematical compensation or normalization of the actual measurement results, correcting for variations in wetted surface area caused by incomplete filling, air bubbles, or leaky measuring chambers while maintaining the ease of operation of 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
This approach enables reliable detection of faulty electrodes and measurement conditions, preventing incorrect measurements by normalizing conductivity values and accounting for changes in the wetted surface area, thus ensuring accurate results.
Implementation Method 1
a first admittance value (apparent conductance) is determined between two electrodes (which should be referred to as the first pair of electrodes). Simultaneously or subsequently, a second apparent conductance between two electrodes (which should be referred to as the second pair of electrodes) of the sensor is determined
Implementation Method 2
a liquid measuring medium is first supplied to the sensor. For this liquid transport, capillaries can be used, for example
Data Source
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AI summary
The invention relates to a method and a corresponding system for checking electrochemical sensors with at least two electrodes, wherein i) a liquid measuring medium is first supplied to the sensor; ii) a first apparent conductance (admittance) between two electrodes of the sensor is determined; iii) a second apparent conductance (admittance) between two electrodes of the sensor is determined, and iv) the first and the second apparent conductance are related to each other.