Titration Device Using Ion Exchange Membrane for In Situ Titrant Generation
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Solution Overview
Problem
Conventional coulometric titration methods face issues such as sample dilution errors, concentration polarization, and contamination due to the use of liquid titrants, which limit detection accuracy and require frequent preparation and storage precautions, while also being sensitive to diffusion rates and electrode side reactions.
Innovation Solution
A titration apparatus with an ion source reservoir, an ion exchange membrane barrier, and inert electrodes that generate titrant ions through electrolysis, allowing for precise ion transport into a titration reservoir without bulk liquid flow, enabling efficient and automated titrant generation with minimal sample volume change and reduced contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If liquid titrant reagents are used in conventional titration, then the titration process can be performed with simple apparatus, but the titrant requires frequent preparation and storage precautions to prevent degradation and contamination
Solution Approach 1:
The system generates titrant in situ through electrolysis of water, eliminating the need for external titrant preparation and storage. The titrant is produced on-demand by the system itself using electricity as the only reagent, thereby achieving self-service and eliminating degradation and contamination issues associated with liquid titrants.
Solution Approach 2:
The patent replaces the chemical storage and dispensing system with an electrochemical generation system. Instead of using pre-prepared liquid titrants that require mechanical handling and storage, the system uses electricity to generate titrant through electrolysis, substituting a mechanical/chemical system with an electrical one.
2Productivity
If titrant is generated electrochemically in the same cell as the titration, then the titrant is readily available, but sample dilution errors and contamination occur due to bulk liquid flow
Solution Approach 1:
The system divides the electrochemical cell into two distinct compartments: a generation compartment where titrant is produced through electrolysis, and a titration compartment where the actual titration occurs. The ion-exchange membrane separates these compartments, allowing ion transport while preventing bulk liquid mixing. This segmentation enables continuous titrant generation without sample dilution or contamination.
Solution Approach 2:
An ion-exchange membrane acts as an intermediary between the generation and titration compartments. It selectively transports ions to maintain electrical neutrality while blocking bulk liquid flow, thereby enabling titrant generation without direct mixing of the generation electrolyte with the sample solution.
3Productivity
If conventional coulometric titration uses salt solution for electrolyte, then the titration can proceed, but conductivity detectors cannot be used because the salt solution overwhelms the detector response
Solution Approach 1:
The system separates the electrolyte function into two distinct compartments: the generation compartment contains the salt solution electrolyte needed for efficient electrolysis, while the titration compartment contains only the sample and minimal supporting electrolyte. This segmentation allows high-concentration salt solution to be used for titrant generation without interfering with sensitive conductivity detection in the titration compartment.
4Ease of operation
If liquid titrant is added to sample, then neutralization occurs, but carbonate errors and contamination build up requiring frequent replenishment
Solution Approach 1:
The system continuously generates fresh titrant through electrolysis of water in the generation compartment, eliminating the need for external titrant replenishment. The electrochemical generation produces titrant on-demand at a rate controlled by the applied current, ensuring continuous availability without preparation or storage concerns.
Solution Approach 2:
The electrolytic generation of titrant operates continuously throughout the titration process, maintaining a steady supply of fresh titrant. This continuous generation eliminates interruptions for titrant replenishment and ensures the titration can proceed without time loss for preparation and storage maintenance.
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 minimizes sample dilution errors, eliminates contamination risks, and allows for precise, automated titrant generation with 100% faradic efficiency, reducing the need for matrix adjustments and storage concerns, while maintaining accurate detection without interference from dissolved gases or carbonate errors.
Implementation Method 1
an ion exchange membrane barrier capable of passing ions of one charge, positive or negative, from said ion source solution to said titration reservoir, but of blocking bulk liquid flow
Implementation Method 2
applying an electrical potential between the first and second electrodes to cause the selected ions to be transported from an ion source reservoir through the membrane barrier into sample solution in the titration reservoir to titrate the sample solution
Data Source
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AI summary
A titration apparatus comprising a titration reservoir for a non-flowing sample solution to be titrated; an ion source reservoir comprising an ion source solution of selected ions; an ion exchange membrane barrier capable of passing ions from the ion source solution to the titration reservoir, but of blocking bulk liquid flow; a first electrode in electrical communication with the ion source reservoir; and a second electrode in electrical communication with the titration reservoir. Also, an electrolytic titrant generator is claimed for use in the titration apparatus.