Cannula-Blade Sampling for Thin-Layer Chromatography Analysis

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Solution Overview

Problem

Existing methods for obtaining samples from thin-layer chromatography plates suffer from issues such as inadequate sealing, damage to the separation layer, difficulty in handling thin layers, and inability to analyze small, closely spaced specimen areas due to limitations in sealing and solvent use, leading to distorted analysis and incomplete evaluation.

Innovation Solution

A method using a cannula with a blade at its receiving opening to mechanically remove samples from the thin-layer plate, combined with a specimen chamber and optional reduced pressure to ensure precise collection, allowing for small sample sizes and minimal solvent use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hollow cylinder with a ring-shaped seal is pressed onto the thin-layer plate to delimit and seal off a specimen area, then sealing of the specimen area is achieved, but the contact pressure required for reliable sealing damages the coating of separating material and causes cracks to form

Engineering Contradiction:

Improvesealing reliabilityVSAvoiddamage to separation layer

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical sealing system (hollow cylinder with ring-shaped seal requiring contact pressure) with a capillary system that uses capillary forces and surface tension to retain the solvent and specimen mixture. The capillary action naturally confines the liquid without requiring external pressure, thereby avoiding damage to the separation layer while maintaining sealing effectiveness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces the capillary structure as an intermediary between the solvent and the separation layer. The capillary acts as a mediator that retains the solvent through its walls, allowing the specimen to be dissolved and transferred without direct contact pressure between a sealing element and the separation layer, thus preventing crack formation and coating damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If high contact pressure is applied by the hollow cylinder with ring-shaped seal to achieve adequate sealing, then sealing effect is improved, but the spatial separation between adjacent arrangements must be large, preventing complete evaluation of closely adjacent specimen areas

Engineering Contradiction:

Improvesealing effectVSAvoidspatial separation between specimen areas

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent replaces the pressure-dependent mechanical sealing system with a capillary-based retention system. The capillary structure uses surface tension and capillary action to confine the solvent and specimen mixture, eliminating the need for high contact pressure. This allows specimen areas to be placed close together without interference, as the capillary action naturally confines each specimen area independently.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the separation layer is made thin (less than 100 μm) for fast thin-layer chromatography with little specimen material, then productivity is improved, but the separating material cannot be compacted sufficiently to effect reliable sealing with the hollow cylinder method

Engineering Contradiction:

Improvespeed of thin-layer chromatographyVSAvoidsealing reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces the mechanical compression-based sealing method with a capillary action-based retention system. The capillary structure relies on surface tension and capillary forces to confine the solvent, which are effective regardless of the separation layer thickness. This enables reliable operation with thin separation layers (less than 100 μm) that cannot be sufficiently compacted by mechanical pressure, thereby maintaining high productivity while ensuring reliable specimen area definition.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If a laser beam is used to remove the separating material and specimen material from the support plate, then spatial resolution is improved, but quantitative analysis becomes impossible due to distorted removal behavior of different components

Engineering Contradiction:

Improvespatial resolutionVSAvoidquantitative analysis accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent replaces the thermal/laser removal method with a mechanical scraping method using a blade. The blade mechanically removes the separation layer and embedded specimen material without the thermal effects that cause differential removal of components. This mechanical approach maintains spatial resolution while enabling quantitative analysis, as all components are removed uniformly based on their physical presence rather than their thermal or optical properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables high spatial resolution and accurate analysis with sharp measurement peaks, reducing contamination and enabling analysis of small specimen amounts, even below detection limits, while minimizing damage to the thin-layer plate.

Implementation Method 1

the sample is removed from a surface of the thin-layer plate by means of a blade disposed at a receiving opening of a cannula

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

the sample removed by means of the blade is fed through the cannula to the specimen chamber connected to the cannula

Methodology Applied

Scientific EffectGravity: Gravitation

Implementation Method 3

a reduced pressure is generated in the specimen chamber in order to suck the sample removed from the thin-layer plate by means of the cannula through the receiving opening of the cannula and through the cannula into the specimen chamber

Methodology Applied

Scientific EffectSuction: Suction

Data Source

PatentUS12366562B2Method and device for the provision of a sample

Publication Date: 2025.07.22 MERCK PATENT GMBH

AI summary

A method is provided for preparing a sample of a specimen to be analysed from a thin-layer plate in thin-layer chromatography. The sample is removed from a surface of the thin-layer plate by means of a blade disposed at a receiving opening of a cannula and fed through the cannula to a specimen chamber connected to the cannula. A reduced pressure can be generated in the specimen chamber to suck the sample removed from the thin-layer plate by means of the cannula through the receiving opening into and through the cannula and into the specimen chamber. After removal and feed of the sample, the specimen chamber can be filled with a solvent to dissolve the sample. The cannula with the blade can be deflected against a spring force or the blade can be deflected against a spring force relative to the receiving opening of the cannula at the receiving opening of the cannula to prevent the blade from penetrating into the thin-layer plate with an excessive contact pressure during the removal of the sample from the thin-layer plate.