Capillary Retaining Frit Nested Design for Chromatography

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Solution Overview

Problem

Conventional chromatographic columns face challenges with peak dispersion due to large dead volumes, especially in capillary columns, which affect separation efficiency and fidelity, and existing retaining frits are difficult to use effectively with larger diameters.

Innovation Solution

The use of a retaining frit within a capillary column with a smaller inner diameter, sealed using a polymeric substance like poly(dimethylsiloxane), minimizes void volume and enhances chromatographic efficiency by reducing transfer diameter and facilitating fluidic connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional retaining frits are used in cartridge type format, then they can retain sorbent material, but they create large dead volumes that lead to peak dispersion

Engineering Contradiction:

Improvesorbent retentionVSAvoidpeak dispersion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The retaining frit is nested within the capillary column structure, with the frit's outer diameter substantially equal to the capillary's inner diameter. This nesting eliminates dead volume between the frit and column walls while maintaining effective sorbent retention through the frit's porous structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The retaining frit is constructed as a porous element that allows fluid passage while physically retaining the sorbent material. The porous structure provides the necessary retention function without creating large dead volumes, as the frit's dimensions are optimized to match the capillary column geometry.

Inventive Principle:

Principle #31Porous materials

2Manufacturing precision

If retaining frits are made with larger inner diameter to maximize stationary phase surface area, then separation efficiency improves, but fluidic connections become more difficult

Engineering Contradiction:

Improveseparation efficiencyVSAvoidfluidic connection

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The frit structure exhibits local quality variations: the region in contact with the capillary wall provides structural support and sealing, while the central luminal region maintains an open fluidic pathway. This local differentiation allows the frit to achieve both large effective diameter for stationary phase support and proper fluidic connectivity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention transitions from considering only the frit's inner diameter to considering the relationship between outer diameter, inner diameter, and capillary dimensions. By optimizing the outer diameter to match the capillary inner diameter, the system achieves proper fluidic connection while maintaining sufficient luminal area for efficient chromatography.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Productivity

If retaining frit is disposed within capillary column, then void volume is minimized and separation efficiency increases, but the frit must be precisely sized and sealed

Engineering Contradiction:

Improvechromatographic efficiencyVSAvoidfrit positioning and sealing

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention specifies precise dimensional parameters for the frit, with the outer diameter being substantially equal to the capillary inner diameter. This parameter matching eliminates void spaces and ensures proper sealing, thereby maximizing chromatographic efficiency while providing clear manufacturing guidelines.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

A polymeric sealing substance is introduced as an intermediary between the frit and capillary wall to ensure proper sealing and positioning. This sealing layer compensates for minor dimensional variations and ensures reliable fluidic connection without compromising the minimized void volume design.

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 design significantly improves chromatographic efficiency and fidelity by minimizing void volume and maintaining peak shape, resulting in better separation and reduced sample loss, as demonstrated by improved chromatograms compared to conventional columns.

Implementation Method 1

a glue-like polymeric substance like poly(dimethylsiloxane) is disposed between the inner surface of the analytical capillary column's surface and the outer surface of the retaining capillary frit This glue-like substance serves as a sealant

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

The luminal areas of the retaining frit and analytical column align so as to facilitate movement of analyte from the retaining frit to the analytical column

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS7938961B2Capillary loop with a built-in retaining frit

Publication Date: 2011.05.10 WATERS TECHNOLOGY CORP

AI summary

Disclosed herein are an apparatus and method for effectuating increased chromatographic efficiency in a capillary column by employing a retaining frit disposed within an analytical capillary. By disposing the retaining frit within the analytic capillary, the void volume is significantly minimized. The columns and methods described herein produce a simplified analytical capillary and retaining frit apparatus that provides greater chromatographic efficiency. Additionally, the column of the instant invention maintains chromatographic fidelity by reducing the transfer diameter as well as facilitating fluidic connections in situ.