Replaceable Electrospray Emitter Assembly for Leak-Safe Low-Dead-Volume LC-MS
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Solution Overview
Problem
Current electrospray emitter systems for mass spectrometry face challenges such as high dead volume, complex user assembly leading to leaks and poor connections, and the inability to easily replace the emitter when it becomes clogged, which affects chromatographic separation and detection sensitivity.
Innovation Solution
A low dead volume, replaceable electrospray emitter assembly that features a female threaded end fitting for engagement with a plug type capillary fitting of the separation column, allowing for easy connection and disconnection, and includes a retractable protective sleeve to protect the emitter tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If users assemble the nano spray emitter with the nano LC column using sleeves and fittings, then the system can be customized and adapted, but this approach is prone to improper connections resulting in leaks, column/emitter breaks, or undesired dead-volumes
Solution Approach 1:
The emitter assembly integrates the emitter, protective sleeve, and connection fitting into a single pre-assembled unit. This merging eliminates the need for users to manually assemble multiple components (sleeves and fittings), thereby preventing improper connections, leaks, and unwanted dead volumes while maintaining adaptability through the standardized fitting interface.
Solution Approach 2:
The emitter, protective sleeve, and connection fitting are pre-assembled into a complete emitter assembly before reaching the user. This preliminary assembly ensures proper connection geometry and sealing, eliminating the risk of user assembly errors while maintaining the ability to customize by selecting different pre-assembled units with varying specifications.
2Volume of stationary object
If the emitter is directly attached to the nano column outlet using a union, then the extra-column dwell volume is minimized, but the system requires precise alignment and proper connection which may be difficult to achieve
Solution Approach 1:
The connection fitting is integrated directly onto the emitter assembly, eliminating the need for separate unions and transfer lines. This merging minimizes the extra-column dwell volume by reducing the number of connection interfaces and dead volume-containing components, while the standardized fitting design ensures ease of connection through simple alignment and attachment.
3Volume of stationary object
If a microchip based LC-ESI device integrates a trapping column, a separation column, and an electrospray emitter within a single structure, then the dead volume is reduced, but the chromatographic performance is currently not able to compete with that of conventional non-chip based systems
Solution Approach 1:
The system separates the microchip-based separation column from the electrospray emitter, with each optimized for its specific function. The emitter assembly includes a precisely manufactured emitter with controlled inner diameter and length, while the separation column can be independently optimized. This segmentation allows both components to achieve their optimal performance without the compromises required by fully integrated chip-based systems.
4Measurement precision
If small inner diameter columns are used to reduce sample complexity and increase MS sensitivity, then the operating flow rate decreases which is suitable for high sensitive MS detection, but the system becomes more sensitive to dead volume effects
Solution Approach 1:
The emitter and connection fitting are merged into a single integrated assembly that minimizes dead volume. The emitter itself is designed with a small inner diameter matching the separation column, ensuring smooth transition and minimizing band broadening. This integrated design reduces the overall dead volume in the system, making it compatible with the low flow rates required for high sensitivity MS detection with small inner diameter columns.
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 significantly reduces dead volume, simplifies user assembly, allows for easy replacement of the emitter, and enhances chromatographic separation and detection sensitivity, achieving performance comparable to fully integrated systems.
Implementation Method 1
Electrospray ionization (ESI) is a technique to produce gas phase ions from liquid solution while applying a high voltage to create aerosol
Implementation Method 2
A retractable protective sleeve is provided which moves to a retracted position to uncover the tip of the emitter when the emitter is in use
Data Source
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AI summary
An electrospray emitter assembly for interfacing a separation column to a mass spectrometer is disclosed. An emitter capillary includes an inlet end and an outlet end. A fitting is coupled to the inlet end of the emitter, configured to be removably connected to the separation column. A stop with a defined through hole is integrated proximate the inlet end of the emitter to produce a path for liquid to flow from the separation column to the emitter via the through hole where a voltage is applied to the liquid entering the emitter.