Zwitterionic Chromatographic Material for Polar Molecule Separation
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Solution Overview
Problem
Conventional chromatographic techniques, such as reversed-phase and ion exchange chromatography, face limitations in retaining highly polar molecules and offer limited selectivity, especially for pharmaceutical applications, due to inadequate hydrophobic retention and compatibility issues with mass spectrometry.
Innovation Solution
A zwitterionic ligand with a general formula is covalently bonded to a substrate, providing a zwitterionic/reversed-phase mixed-mode chromatographic material that combines hydrophobic interaction and ionic interaction functionalities, allowing for adjustable selectivity and compatibility with mass spectrometry without the need for ion-pairing agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reversed-phase chromatography is used, then hydrophobic retention is achieved, but highly polar molecules cannot be retained and selectivity is limited
Solution Approach 1:
The patent combines reversed-phase ligands (providing hydrophobic retention) and ion-exchange ligands (providing ionic retention) into a single mixed-mode stationary phase. This merging allows the column to retain both hydrophobic and ionic analytes simultaneously, resolving the contradiction between achieving hydrophobic retention and maintaining selectivity for polar molecules.
Solution Approach 2:
The stationary phase is constructed as a composite material containing both reversed-phase functional groups (e.g., C18) and ion-exchange functional groups (e.g., sulfonic acid or amine groups) on the same silica support. This composite structure enables dual retention mechanisms to operate concurrently, improving both reliability and adaptability.
2Reliability
If ion exchange chromatography is used, then ionic molecules are separated, but hydrophobic retention is inadequate and use in organic molecule separations is limited
Solution Approach 1:
The mixed-mode stationary phase merges ion-exchange functionality with reversed-phase functionality, allowing the column to provide both ionic retention (for separating ionic molecules) and hydrophobic retention (for retaining organic molecules). This resolves the limitation of inadequate hydrophobic retention in pure IEX systems.
3Reliability
If ion pairing chromatography is used, then ionic analytes can be separated on reversed-phase column, but extended equilibration time and complicated mobile phase with high salt content are required
Solution Approach 1:
The invention extracts the ion-exchange functionality directly into the stationary phase structure, eliminating the need for ion-pairing agents in the mobile phase. By incorporating ion-exchange ligands covalently bonded to the silica support, the system achieves ionic retention through the stationary phase itself, removing the requirement for extended equilibration and high salt content mobile phases.
4Reliability
If ion pairing agents are used, then ionic analyte separation is improved, but compatibility with mass spectrometry deteriorates
Solution Approach 1:
The invention removes ion-pairing agents from the mobile phase by incorporating ion-exchange functionality directly into the stationary phase. This extraction of the ion-exchange function from the mobile phase to the stationary phase eliminates the harmful salts and ion-pairing agents that interfere with mass spectrometry detection, while maintaining separation performance.
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 material offers unique selectivity for a broad range of applications, enabling efficient separation of both hydrophobic and ionic analytes with flexible chemistry, reducing the need for extended equilibration times and complex mobile phases, and allowing for lower salt content in chromatographic separations.
Implementation Method 1
combines hydrophobic interaction and ionic interaction functionalities
Implementation Method 2
combines hydrophobic interaction and ionic interaction functionalities
Implementation Method 3
separation of a sample comprising a mixture of components (also termed analytes) is achieved by conveying the sample in a liquid mobile phase through a stationary phase in a column, thereby causing the sample to separate into its components due to different partitioning between the mobile and stationary phases
Data Source
AI summary
A chromatographic material comprising a zwitterionic ligand covalently bound to a substrate, the ligand preferably has a formula II:whereinR1, R2, R3 are independently selected from an oxygen atom that is configured to connect to a substrate atom in the substrate, an oxygen atom that is configured to connect to a silicon atom of an adjacent ligand, a hydroxyl group, a halogen atom, an alkoxy group, a dialkylamino group, an acyl group, an alkyl group, or an aryl group;L1, L2 and L3 are independently hydrophobic moieties; each containing 2 to 30 carbon atoms, wherein there are at least 10 carbon atoms in the combined chain lengths of L1, L2 and L3;X is an O atom, S atom, amide group or sulfonamide group;n is 0 or 1;R4, R5 are independently selected from a hydrogen atom or a hydrocarbon moiety containing 1 to 20 carbon atoms; andRf is a negatively charged moiety comprising a sulfonic, carboxylic, or phosphonic functional group.