Switchable Loop Valve for Low-Pressure Chromatographic Elution

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Solution Overview

Problem

Existing solid phase extraction (SPE) systems for LC-MS analysis face challenges with leakage due to high back pressure, leading to incomplete and irreproducible elution, which affects chromatographic resolution and analysis time.

Innovation Solution

The introduction of a switchable loop between the pipette tip and the separation column allows for low-pressure elution into the loop, followed by valve switching to connect the loop with the separation column, thereby eliminating the need for high-pressure elution and reducing leakage issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If direct elution through the pipette tip into the separation column is used, then chromatographic resolution is maintained, but high back pressure causes leakage and incomplete elution

Engineering Contradiction:

Improveelution completenessVSAvoidback pressure

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

A recipient socket is introduced as an intermediary component between the pipette tip and the separation column. This socket provides a low-resistance pathway that reduces back pressure during elution, preventing leakage while maintaining chromatographic resolution through proper fluid communication design.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If high-pressure elution is used to overcome back pressure, then elution speed increases, but leakage occurs at the pipette tip connections

Engineering Contradiction:

Improveelution speedVSAvoidleakage

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The recipient socket acts as a mediator that distributes and manages the pressure during elution, providing a stable connection interface that prevents leakage while enabling efficient fluid transfer from the pipette tip to the separation column.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the pressure distribution parameters by introducing a low-resistance pathway through the recipient socket, allowing optimized elution speed without exceeding the pressure tolerance of the pipette tip connections.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If nano-flow LC parameters are used, then analytical sensitivity is improved, but cycle time increases due to low flow rates

Engineering Contradiction:

Improveanalytical sensitivityVSAvoidcycle time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The fluid pathway is segmented into distinct functional zones: the nano-flow separation column for high-sensitivity analysis, and the low-resistance recipient socket for rapid fluid transfer. This segmentation allows different flow rates in different segments, optimizing both sensitivity and cycle time.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The recipient socket serves as a mediator between the slow nano-flow separation process and the fast transfer requirement, enabling rapid elution without compromising the low flow rate conditions needed for analytical sensitivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Device complexity

If the pipette tip is directly connected to the separation column, then device complexity is minimized, but leakage occurs due to high pressure

Engineering Contradiction:

Improvesystem complexityVSAvoidconnection reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The recipient socket is a relatively simple intermediary component that provides robust mechanical and fluid connections, enhancing system reliability without significantly increasing overall device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enables high-flow rate elution without back pressure, significantly reducing cycle time and maintaining chromatographic resolution by regaining resolving power through phase shift or eluent modification.

Implementation Method 1

a cartridge enclosing a sorbent for binding the analytes in the solution

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

a valve providing access to a holding-loop with or without sorbent, wherein the valve is switchable to a position following the elution from the cartridge

Methodology Applied

Scientific EffectMechanical movement: Mechanical Force

Implementation Method 3

passing a liquid (i.e. a mobile phase) that contains the sample mixture through a conduit

Methodology Applied

Scientific EffectAdvection: Advection

Data Source

PatentUS12298284B2System for subjecting a sample to chromatographic analysis

Publication Date: 2025.05.13 EVOSEP APS

AI summary

There is provided a system for separation of analytes in a solution. The system encompasses a disposable cartridge enclosing a sorbent for binding the analytes in a solution and a conduit establishing a fluid link to a valve having a holding-loop to achieve elution through the cartridge at low pressures. The valve is switchable to a position following the elution from the cartridge for emptying through an outlet port at high pressures such as those required for moving liquid through chromatographic columns.