Flow Splitting System for Multi-Dimensional Liquid Analysis

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Solution Overview

Problem

Current flow splitters in multidimensional liquid chromatography systems face challenges in maintaining uniform flow splitting due to variable viscosity and temperature changes, leading to unpredictable flow rates and solvent concentrations, which limits the resolution and efficiency of two-dimensional liquid chromatography.

Innovation Solution

A flow splitting system utilizing a T-style junction with a positive displacement pump and adjustable pressure regulator, allowing for controlled flow rates and pressures, coupled with a 3-port or 6-port valve system to manage flow between HPLC systems and a mass spectrometer, ensuring consistent sampling and preservation of chromatographic resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If resistive tubing elements are used to split liquid flow, then flow splitting is achieved, but uniform flow splitting cannot be maintained due to variable viscosity and temperature changes

Engineering Contradiction:

Improveflow splitting uniformityVSAvoidresponse to viscosity and temperature changes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the passive resistive tubing system with an active pump-driven flow splitting system. The pump mechanically controls the flow division between dimensions, substituting the unreliable resistive mechanism with a controllable mechanical system that can maintain consistent flow ratios despite changes in mobile phase properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the control parameter from passive resistance to active pump displacement control. By controlling the pump's displacement and speed, the system can precisely regulate flow splitting ratios, making the flow division independent of viscosity and temperature variations that affect resistive systems.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If HPLC mobile phase flow rate is reduced to match mass spectrometer capacity, then mass spectrometer analysis is enabled, but chromatographic resolution is reduced

Engineering Contradiction:

Improvecompatibility with mass spectrometerVSAvoidchromatographic resolution

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent divides the HPLC effluent flow into two separate streams using a flow splitter: one stream is reduced in flow rate to match the mass spectrometer's capacity, while the other stream maintains the original high flow rate to preserve chromatographic resolution. This segmentation allows both requirements to be satisfied simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flow splitter acts as an intermediary device between the HPLC system and the mass spectrometer. It receives the high-flow HPLC effluent and selectively directs a portion to the mass spectrometer at the appropriate reduced flow rate, while allowing the remainder to continue at full flow, thus mediating between the conflicting flow rate requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If fraction collection is used to analyze first dimension separation, then total effluent volume is collected, but re-injection of representative samples is required for second dimension separation

Engineering Contradiction:

Improvetotal effluent volume collectionVSAvoidfraction collection and re-injection process

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The pump-driven flow splitter enables continuous direct coupling between the first and second dimension separations. Instead of collecting fractions and then re-injecting them in discrete steps, the system maintains continuous flow from the first dimension through the flow splitter directly into the second dimension, eliminating the interruption and additional processing steps.

Inventive Principle:

Principle #20Continuity of useful action

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 system achieves precise control over flow rates and solvent concentrations, enabling consistent injection of representative samples into the second dimension separation column, thereby enhancing the resolution and reliability of multidimensional liquid chromatography analyses.

Implementation Method 1

a second outlet for permitting directly flow controlled outflow therefrom. The second outlet is fluidly coupled to a positive displacement pump

Methodology Applied

Scientific EffectPositive displacement: Displacement

Implementation Method 2

The flow restricting device creates a pressure in the junction from 1 kilopascal to 10,000 kilopascals

Methodology Applied

Scientific EffectPressure regulation: Pressure Increase

Data Source

PatentUS11692980B2Valve and splitting system for multi-dimensional liquid analysis

Publication Date: 2023.07.04 REGENTS OF THE UNIVERSITY OF MINNESOTA

AI summary

A multi-dimensional liquid analysis system includes a flow splitter for separating mobile phase outflow from a first dimension liquid analysis system into first and second liquid split outlet flows. Volumetric flow rate control of the split outlet flows is provided by a flow control pump which withdraws one of the split outlet flows from the flow splitter at a controlled withdrawal flow rate to define the other split outlet flow rate as the difference between the outflow rate from the first dimension system and the withdrawal flow rate. In this manner, accurate and consistent flow division can be accomplished, which is particularly useful for multi-dimensional liquid analysis.