Protein Quantification Reagent for False-High Interference Control

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Solution Overview

Problem

Existing methods for quantifying protein using a metal-dye complex in clinical specimens, particularly in urine and spinal fluid, suffer from false high values due to interference from components like oxalic acid and nitrite ions, leading to inaccurate results.

Innovation Solution

The method involves reacting protein with a metal-dye complex in the presence of an aromatic carboxylic acid or its salt, specifically using monocyclic or bicyclic aromatic carboxylic acids like benzoic acid, in combination with additional compounds such as aliphatic amines, aniline derivatives, or polyhydric alcohols, to improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a metal-dye complex (e.g., pyrogallol red-molybdenum complex) is used to quantify protein, then the method can be applied to clinical specimens such as urine and spinal fluid, but false high values occur due to interference from components like oxalic acid and nitrite ions

Engineering Contradiction:

Improveapplicability to clinical specimensVSAvoidaccuracy of protein quantification

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

An aromatic carboxylic acid or its salt is introduced as an intermediary substance that selectively binds to interfering components (oxalic acid, nitrite ions) in the specimen, preventing them from reacting with the metal-dye complex. This mediator protects the measurement system from interference while allowing the protein quantification to proceed accurately

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The interfering components (oxalic acid, nitrite ions) that cause false high values are converted from harmful factors into manageable ones by having them selectively bind to the aromatic carboxylic acid. This transformation allows the interfering substances to be sequestered in a controlled manner, converting their harmful interference into a benign binding interaction that protects the measurement

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If chelating agents or metal ions are added to bind interfering substances, then negative errors are reduced, but the measurement time increases and automatic analysis becomes difficult

Engineering Contradiction:

Improveaccuracy of protein quantificationVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The chemical parameters of the reaction system are optimized by selecting aromatic carboxylic acids with specific structural characteristics (monocyclic or bicyclic, with two or less carboxyl groups). This parameter optimization allows for rapid binding of interfering substances without requiring long incubation times, enabling the method to be adapted for automatic analysis

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If components are added to reduce interference from coexisting substances, then negative errors are reduced, but the complexity of the reagent increases

Engineering Contradiction:

Improveaccuracy of protein quantificationVSAvoidreagent composition complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The aromatic carboxylic acid serves multiple functions simultaneously: it binds to interfering components (oxalic acid, nitrite ions), maintains the stability of the metal-dye complex, and does not interfere with the protein-binding reaction. This multi-functionality reduces the need for multiple separate additives, simplifying the overall reagent composition while maintaining measurement accuracy

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 significantly reduces false high values, enabling more precise quantification of protein concentrations, especially in high value ranges, and is suitable for automatic analysis.

Implementation Method 1

using a complex in which a metal is coordinated with a dye and of which an absorption wavelength shifts when the protein binds to the complex

Methodology Applied

Scientific EffectAbsorption wavelength shift: Absorption Spectroscopy

Implementation Method 2

reacting the protein with the complex in the presence of an aromatic carboxylic acid or a salt thereof... significantly reduces false high values

Methodology Applied

Scientific EffectChemical inhibition:

Data Source

PatentEP4653870A1Method and reagent for quantifying protein

Publication Date: 2025.11.26 NITTO BOSEKI CO LTD

AI summary

The present invention alleviates the problem of false high values in a method for quantifying protein by using a complex in which a metal is coordinated with a dye. In this method for quantifying a protein in a specimen by using a complex in which a metal is coordinated with a dye, the protein is reacted with the complex in the presence of an aromatic carboxylic acid or a salt thereof.