Adjustable Flow Splitter for Liquid Chromatography Sample Dilution

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Solution Overview

Problem

Liquid chromatography systems face challenges in sample dilution, particularly when strong solvents are used, leading to peak broadening, peak distortion, and sample breakthrough, and manual dilution is impractical due to distance and human error concerns.

Innovation Solution

A fluidic network with a selectable flow restriction device and flow splitter is used to dilute chromatographic samples by splitting solvent flows, allowing for adjustable dilution ratios without additional pumps, ensuring sample components are retained at the chromatographic column head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual dilution is performed by a technician, then sample dilution can be achieved, but it results in significant delay, risk of contamination, human error, and additional tracking inconvenience

Engineering Contradiction:

Improvedilution accuracyVSAvoiddilution time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs dilution automatically using integrated flow splitters and solvent delivery mechanisms, eliminating the need for manual technician intervention. The chromatography system self-regulates solvent flow ratios to achieve precise dilution of strong solvent samples before injection.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

A flow splitter acts as an intermediary device that divides the mobile phase flow into multiple streams, allowing automated mixing with sample solvent. This intermediary mechanism enables precise control of dilution ratios without direct human handling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If strong solvent is used for sample dissolution, then sample solubility is improved, but it causes peak broadening, peak distortion, or sample breakthrough

Engineering Contradiction:

Improvesample solubilityVSAvoidchromatographic peak shape

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The system performs preliminary dilution of the strong solvent sample using weakened mobile phase before the sample enters the chromatographic column. This pre-dilution step prevents peak broadening and distortion while maintaining complete sample dissolution.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The mobile phase composition is dynamically adjusted by changing the solvent flow ratio through the flow splitter. By modifying the mobile phase strength parameter (solvent-to-water ratio), the system optimizes both sample solubility and peak shape control.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If additional equipment is added for sample dilution, then dilution control is improved, but device complexity increases

Engineering Contradiction:

Improvedilution controlVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The flow splitter serves multiple functions: it divides mobile phase flow for dilution, enables gradient elution programming, and provides flexible sample injection capabilities. This multi-functional approach achieves versatile dilution control without adding separate dedicated dilution equipment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 prevents peak broadening and distortion by diluting samples effectively, allowing for precise control of dilution ratios and reducing the need for additional equipment, thereby improving chromatographic separation efficiency.

Implementation Method 1

The flow splitter divides an inlet flow received at the inlet port into a first outlet flow at the first outlet port and a second outlet flow at the second outlet port

Methodology Applied

Scientific EffectFluid flow splitting:

Implementation Method 2

Each of the flow restrictors may include a fluidic channel having a diameter that is different from the diameter of each of the other fluidic channels of the other flow restrictors

Methodology Applied

Scientific EffectFlow resistance:

Implementation Method 3

Liquid chromatography systems sometimes require the dilution of a sample before the sample is injected into the mobile phase flowing to a chromatography column

Methodology Applied

Scientific EffectChromatography: Chromatography

Data Source

PatentEP4065971B1Sample injection for liquid chromatography using split solvent flow

Publication Date: 2025.01.01 WATERS TECHNOLOGY CORP

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AI summary

Described herein are a selectable flow restriction device and a fluidic network for chromatographic sample dilution during injection. A selectable flow restriction device is used in combination with a splitter to define an adjustable splitter (42) for separating a high-pressure solvent flow into two separate solvent flows having the same solvent composition. The first solvent flow passes to a sample manager (24) where a sample is injected as a discrete fluidic plug at an injection valve into a flow comprising at least one solvent. The second solvent flow is merged at a combiner (40) downstream from the location of injection with the first solvent carrying the sample fluidic plug. The second solvent flow dilutes the sample plug during the mixture of the two solvent flows.