Ion suppressor membrane resistance for noise reduction
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Solution Overview
Problem
Ion suppressors in ion chromatography face issues with noise generation and shortened lifespan due to local gas generation in the regeneration liquid channel, leading to degradation of ion exchange membranes and reduced current efficiency.
Innovation Solution
Incorporating an ion permeable membrane with higher resistivity and lower swelling ratio than the ion exchange membrane, disposed in contact with the ion exchange membrane, to increase resistance and suppress local gas generation, and using a mesh material with varying charge density in the regeneration liquid channels to adjust resistance and reduce bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ion exchange membranes are used in the ion suppressor to enable ion exchange and electrodialysis, then the electric conductivity of the eluent is decreased and measurement sensitivity is improved, but local gas generation occurs in the regeneration liquid channel causing baseline noise and membrane degradation
Solution Approach 1:
A gas permeable membrane is introduced as an intermediary layer between the ion exchange membrane and the regeneration liquid channel. This intermediary allows generated gas to pass through the membrane and be discharged, preventing gas accumulation that causes baseline noise, while maintaining the ion exchange function of the ion exchange membrane.
Solution Approach 2:
A gas permeable membrane with specific porosity is used in the regeneration liquid channel. The porous structure allows gas molecules to pass through while maintaining structural integrity and enabling controlled gas discharge, thereby eliminating the harmful effect of gas accumulation on measurement baseline.
2Measurement precision
If ion exchange membranes are used to achieve high-sensitivity detection, then the electric conductivity is decreased, but the lifespan of the ion suppressor is shortened due to membrane degradation from local gas generation
Solution Approach 1:
The gas generation that previously caused harmful effects (noise and degradation) is converted into a beneficial discharge process. The gas permeable membrane channels the generated gas away from the ion exchange membrane, preventing degradation while maintaining the electrodialysis function that provides high detection sensitivity.
Solution Approach 2:
The gas permeable membrane acts as a protective intermediary that shields the ion exchange membrane from direct contact with generated gas, preventing oxidative degradation and extending membrane lifespan while preserving the sensitivity-enhancing electrodialysis function.
3Productivity
If the ion suppressor structure includes regeneration liquid channels and ion exchange membranes, then ion exchange functionality is achieved, but current efficiency is reduced due to local gas generation
Solution Approach 1:
Gas is extracted and removed from the system through the gas permeable membrane, which allows selective passage of gas molecules while retaining liquid flow paths. This extraction of harmful gas phase products eliminates the negative impact on current efficiency while preserving the ion exchange functionality.
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 solution effectively reduces baseline noise and extends the life of the ion exchange membrane by uniformly distributing ion exchange and suppressing local gas generation, thereby improving the overall performance and longevity of the ion suppressor.
Implementation Method 1
two ion exchange membranes 41 and 43 between an anode 21 and a cathode 23
Implementation Method 2
the electric conductivity of an eluent is decreased by electrodialysis
Implementation Method 3
When a voltage is applied between the anode 221 and the cathode 223
Implementation Method 4
Incorporating an ion permeable membrane with higher resistivity and lower swelling ratio than the ion exchange membrane, disposed in contact with the ion exchange membrane, to increase resistance
Implementation Method 5
using a mesh material with varying charge density in the regeneration liquid channels to adjust resistance and reduce bubble formation
Data Source
AI summary
An ion suppressor includes ion exchange membranes between a pair of electrodes. Regeneration liquid channels are provided in the spaces between the electrodes and the ion exchange membranes, and an eluent channel is provided between the ion exchange membranes. In the space between the electrode and the eluent channel, an element that increases the resistance in the voltage application direction is disposed. For example, ion permeable membranes are disposed in contact with the ion exchange membrane, thereby increasing the resistance in the voltage application direction.