Bipolar Membrane Eluent Generator for Chromatography Purity
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Solution Overview
Problem
Existing two-membrane eluent generators suffer from low eluent purity due to the return of impurity ions from tested samples through ion-exchange membranes, which interferes with subsequent analytical experiments.
Innovation Solution
A two-membrane eluent generator is designed with a bipolar membrane between the regeneration channel and the eluent channel, allowing for the supply of H+ or OH- ions by electrolysis of the regenerant solution while preventing impurity ions from entering the eluent channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional two-membrane eluent generator with cation-exchange and anion-exchange membranes is used, then the eluent can be generated through ion exchange, but impurity ions from tested samples return through the ion-exchange membranes leading to low eluent purity
Solution Approach 1:
The patent divides the membrane system into three distinct membrane layers: a cation-exchange membrane layer, a bipolar membrane layer, and an anion-exchange membrane layer. This segmentation creates separate functional zones where the bipolar membrane acts as a barrier to impurity ions while allowing H+ and OH- transport, thereby resolving the contradiction between maintaining ion exchange functionality and preventing impurity contamination.
Solution Approach 2:
The bipolar membrane serves as an intermediary barrier between the stock solution channel and the eluent channel. It mediates the transport process by selectively allowing H+ and OH- ions to pass through via electrolysis while blocking impurity ions from the regenerant solution, thus protecting the eluent purity without completely blocking ion exchange.
2Adaptability or versatility
If ion-exchange membranes are used to generate eluent, then ion exchange function is achieved, but the membranes cannot prevent impurity ions from returning to the eluent
Solution Approach 1:
The patent employs a composite membrane structure consisting of three different membrane types working together: cation-exchange membrane, bipolar membrane, and anion-exchange membrane. This composite structure combines the ion exchange capabilities of the first and third membranes with the selective barrier function of the bipolar membrane in the middle, achieving both versatile ion exchange function and precise eluent composition control.
Solution Approach 2:
Each membrane layer is assigned a specific local function: the cation-exchange membrane layer handles cation transport, the bipolar membrane layer provides selective barrier function and H+/OH- generation, and the anion-exchange membrane layer handles anion transport. This local quality differentiation allows the system to maintain overall ion exchange versatility while achieving precise control over eluent composition through the specialized bipolar membrane zone.
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 implementation of a bipolar membrane significantly increases the purity of the eluent by preventing impurity ions from contaminating the eluent, thereby enhancing the reliability of subsequent analytical experiments.
Implementation Method 1
hydrogen ions or hydroxide ions generated at the bipolar membrane from electrolysis of the regenerant solution
Implementation Method 2
K+ in the stock solution channel 64 enters the eluent channel 63 through the cation-exchange membrane 61
Data Source
AI summary
Provided is a two-membrane eluent generator and a chromatography detection apparatus. The two-membrane eluent generator includes a stock solution channel; an eluent channel, a first ion-exchange membrane set being arranged between the eluent channel and the stock solution channel, the first ion-exchange membrane set including at least one ion-exchange membrane; a regenerant solution channel, a second ion-exchange membrane set being arranged between the eluent channel and the regenerant solution channel, the second ion-exchange membrane set including one bipolar membrane, wherein hydrogen ions or hydroxide ions generated at the bipolar membrane from electrolysis of a regenerant solution respectively enter different sides of the bipolar membrane, and impurity ions are prevented from entering the eluent channel through the bipolar membrane. The chromatography detection apparatus provided in present disclosure includes the two-membrane eluent generator. The present disclosure applies a bipolar membrane between the regeneration channel and the eluent channel, and is thus capable of supplying corresponding hydrogen ions or hydroxide ions for the eluent channel while preventing impurity ions in the regenerant solution from entering the eluent channel, thereby increasing the purity of the eluent.