Frustoconical Sample Cell for Light Scattering Detectors

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Solution Overview

Problem

Conventional light scattering detectors lack sensitivity and resolution to analyze small molecules with a radius of gyration less than 10 nm, and increasing laser power or sample cell volume leads to cost issues and peak broadening.

Innovation Solution

A light scattering detector with a sample cell design featuring frustoconical outer sections and a cylindrical inner section, where the sample flows directly to the center, and scattered light is collected by multiple detectors positioned to receive forward, back, and right-angle scattered light, minimizing peak broadening and enhancing sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If laser power is increased to increase sensitivity, then sensitivity is improved, but cost increases and device size increases

Engineering Contradiction:
ImprovesensitivityVSAvoidcost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of the sample cell, specifically using frustoconical outer sections with specific taper angles (e.g., 10-20 degrees) and specific length-to-diameter ratios, to optimize light scattering collection efficiency. This allows achieving high sensitivity with lower laser power by improving the optical path geometry rather than increasing input energy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from a conventional cylindrical sample cell to a three-dimensional frustoconical geometry with tapered walls. This dimensional change creates optimized light scattering paths in multiple spatial dimensions, allowing scattered light from small molecules to be collected more effectively by detectors positioned at various angles without requiring increased laser power

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If sample cell volume is increased to increase scattered light intensity, then sensitivity is improved, but peak broadening increases

Engineering Contradiction:
ImprovesensitivityVSAvoidpeak broadening
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent optimizes the sample cell dimensions by using frustoconical sections with specific taper angles and length-to-diameter ratios. This geometric parameter optimization increases the effective light scattering path length and collection efficiency without proportionally increasing the sample volume, thereby maintaining chromatographic resolution while improving sensitivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The frustoconical geometry creates optimized three-dimensional light scattering paths that increase the interaction between light and analyte molecules without requiring a larger sample volume. The tapered walls and specific angular orientations enhance scattered light collection efficiency in multiple directions while keeping the axial length and thus peak broadening minimal

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If conventional sample cell geometry is used, then device complexity is low, but sensitivity and resolution for small molecules are insufficient

Engineering Contradiction:
ImproveresolutionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent modifies the sample cell geometry by incorporating frustoconical outer sections with specific taper angles (e.g., 10-20 degrees) and optimized length-to-diameter ratios. These parameter changes enhance light scattering collection efficiency for small molecules while maintaining a relatively simple single-piece construction that can be manufactured using conventional techniques

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The transition from a conventional cylindrical geometry to a frustoconical three-dimensional geometry creates optimized light scattering paths that improve resolution for small molecules. The tapered walls and angular orientations in three-dimensional space enhance the collection of scattered light without requiring complex multi-component assemblies

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 design enhances the sensitivity and resolution of light scattering detectors without increasing peak broadening, allowing for more precise analysis of small molecules, and does so without the need for high-power lasers or large sample cells.

Implementation Method 1

As the effluent is flowed through the sample cell, the effluent is illuminated by a collimated beam of light (e.g., laser). The interaction of the beam of light and the polymers of the effluent produces scattered light.

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

A light scattering detector with a sample cell design featuring frustoconical outer sections and a cylindrical inner section, where the sample flows directly to the center, and scattered light is collected by multiple detectors positioned to receive forward, back, and right-angle scattered light

Methodology Applied
Scientific EffectLight refraction and focusing: Refraction

Data Source

PatentEP3695208B1Light scattering detectors and sample cells for the same
Publication Date: 2024.09.18 TOSOH CORP
  • EP3695208B1 patent drawingFigure 1A
  • EP3695208B1 patent drawingFigure 1B~1C
  • EP3695208B1 patent drawingFigure 1D

AI summary

Sample cells, light scattering detectors utilizing the sample cells, and methods for using the same are provided. The sample cell may include a body defining a flowpath extending axially therethrough. The flowpath may include a cylindrical inner section interposed between a first outer section and a second outer section. The first outer section may be frustoconical. A first end portion of the first outer section may be in direct fluid communication with the inner section and may have a cross-sectional area relatively smaller than a cross-sectional area at a second end portion thereof. The body may further define an inlet in direct fluid communication with the inner section. The inlet may be configured to direct a sample to the inner section of the flowpath.