Hemoglobin S Analysis via Cation-Exchange HPLC

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Solution Overview

Problem

Current cation-exchange high-performance liquid chromatography methods often result in poorly separated broad peaks or bimodal distributions when analyzing highly retentive hemoglobin S, A2, and A0, especially in deteriorated blood samples, due to slight differences in electric charge and increased metohemoglobin levels, which can impact measurement accuracy.

Innovation Solution

The method involves using an eluent with an azide or cyanide concentration of 0.1 to 50 mmol/L and a pH range of 6.80 to 7.50 near the isoelectric point of hemoglobin to stabilize methemoglobin, allowing for the separation of highly retentive hemoglobins in sharp, symmetrical peaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If cation-exchange HPLC is used to separate hemoglobin components, then separation of hemoglobin components is achieved, but highly retentive hemoglobin S produces broad peaks or bimodal distribution

Engineering Contradiction:
Improvepeak symmetryVSAvoidseparation quality
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the pH parameter of the eluent to be near the isoelectric point of hemoglobin (pH 6.80-7.50), which fundamentally alters the charge state of hemoglobin molecules. This parameter change resolves the contradiction by enabling highly retentive hemoglobin S to elute as sharp, symmetrical peaks while maintaining reliable separation from other hemoglobin components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces azide or cyanide as intermediary substances in the eluent (at concentrations of 0.1 to 50 mmol/L). These intermediaries bind to methemoglobin, stabilizing it and preventing the formation of multiple peak distributions. This intermediary action resolves the peak broadening issue while preserving separation quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If azide or cyanide is added to stabilize methemoglobin, then elution time consistency is improved, but peak separation may deteriorate

Engineering Contradiction:
Improvemethemoglobin stabilityVSAvoidpeak separation
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent optimizes the concentration parameters of azide or cyanide (0.1 to 50 mmol/L) and pH (6.80 to 7.50) to achieve a balance where methemoglobin is stabilized without compromising peak separation. This parameter optimization resolves the contradiction by finding the optimal range where both stability and separation precision are maintained.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional eluent pH (4.0-6.8) is used, then separation is achieved, but highly retentive hemoglobins produce broad peaks

Engineering Contradiction:
Improveseparation capabilityVSAvoidpeak shape
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent shifts the pH parameter from the conventional range (4.0-6.8) to a new range near the isoelectric point (6.80-7.50). This parameter change resolves the contradiction by altering the electrostatic interactions between hemoglobin and the cation-exchange column, enabling highly retentive hemoglobins to elute with sharp, symmetrical peaks while maintaining reliable separation.

Inventive Principle:
Principle #35Parameter changes

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 enables accurate separation of highly retentive hemoglobin S, A2, and A0 in sharp, symmetrical peaks, improving measurement accuracy and reducing the impact of sample deterioration on chromatography results.

Implementation Method 1

separates hemoglobin components in a diluted hemolyzed blood sample by a cation-exchange method based on the difference in positive charge between the hemoglobin components

Methodology Applied
Scientific EffectCation-exchange: Ion Exchange

Implementation Method 2

the trivalent Fe ion in methemoglobin binds to the azide or cyanide, resulting in the conversion of methemoglobin into stable azide metohemoglobin or cyanomethemoglobin

Methodology Applied
Scientific EffectComplex formation: Chemical Bonding

Data Source

PatentEP2533043B1Hemoglobin s analysis method
Publication Date: 2022.11.02 SEKISUI MEDICAL CO LTD
  • EP2533043B1 patent drawingFigure 1
  • EP2533043B1 patent drawingFigure 2(a)~2(c)
  • EP2533043B1 patent drawingFigure 3(a)~3(c)

AI summary

An object of the present invention is to provide a hemoglobin S analysis method, a hemoglobin A2 analysis method, and a hemoglobin A0 analysis method which enable even highly retentive hemoglobin S, hemoglobin A2 and hemoglobin A0 to be separated in sharp, highly symmetrical peaks by means of cation-exchange high-performance liquid chromatography. The present invention relates to a method for analyzing hemoglobin S by cation-exchange high-performance liquid chromatography, the method including utilizing an eluent that contains an azide or a cyanide at a concentration of 0.1 to 50 mmol/L and has a pH of 6.80 to 7.50.