Capillary Electrophoresis Interface Segmented Porous Wall
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Solution Overview
Problem
Conventional CE-MS interfaces face issues with low sensitivity due to analyte dilution in sheath liquids and mechanical fragility of porous regions in sheathless configurations.
Innovation Solution
A capillary electrophoresis-mass spectrometer interface featuring a conductive region with porous and non-porous regions circumferentially positioned about a non-conductive tubing, providing improved mechanical strength and sensitivity by allowing voltage application for separation and ionization without dilution, while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sheathless interface is used to prevent analyte dilution and improve sensitivity, then sensitivity improves, but the porous regions become mechanically fragile
Solution Approach 1:
The capillary wall at the interface region is segmented into alternating porous and non-porous regions along the circumference. The porous regions allow voltage application for ionization while the non-porous regions provide mechanical strength, resolving the contradiction between sensitivity improvement and mechanical fragility
Solution Approach 2:
Different regions of the capillary wall are given different properties: porous regions for electrical conductivity and ionization, non-porous regions for mechanical support. This local differentiation allows the capillary to simultaneously achieve high sensitivity and maintain structural integrity
2Measurement precision
If a sheath liquid is used to facilitate ionization, then ionization efficiency improves, but analyte dilution occurs reducing sensitivity
Solution Approach 1:
The sheath liquid component is extracted/removed from the system. Instead of using a sheath liquid to facilitate ionization, the patent applies voltage directly through the porous capillary wall to the analyte in the capillary, eliminating the dilution effect while maintaining ionization capability
Solution Approach 2:
The capillary structure itself provides the ionization function through its porous regions that conduct voltage directly to the analyte, eliminating the need for an external sheath liquid. The system serves itself by using the capillary wall as both the separation medium and the ionization interface
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 enhances sensitivity and resolution in analyte detection and analysis by preventing analyte dilution and improving mechanical stability, enabling high-quality ionization and separation without compromising the capillary's strength.
Implementation Method 1
The CE instrument applies a voltage across the length of the capillary, causing electroosmotic and electrophoretic movement of the analyte molecules in the capillary
Implementation Method 2
ESI produces ions from highly charged liquid droplets comprising the analyte molecules by an electric field produced near the outlet of the capillary
Implementation Method 3
The conductive region includes porous regions and non-porous regions positioned about a circumference of the non-conductive tubing
Data Source
AI summary
Described is a capillary that interfaces with an analysis system. The capillary comprises a non-conductive tubing and a conductive region proximate to an output end of the non-conductive tubing. The conductive region comprises a plurality of porous regions and non-porous regions positioned about a circumference of the non-conductive tubing. The porous regions separated from each other by the non-porous regions. Advantageously, the arrangement of porous regions provides mechanical stability about the conductive region.