Colorimetric Manganese Detection Under Chlorine Interference

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Solution Overview

Problem

Conventional methods for measuring manganese in aqueous samples are limited by the presence of chlorine or chlorine-containing species, leading to inaccurate results, and some methods are not environmentally friendly or compliant with regulatory guidelines.

Innovation Solution

A method using a dechlorination reagent comprising iron(II) and potassium iodide to reduce chlorine interference, followed by oxidation of manganese to Mn(IV) with 3,3',5,5'-tetramethylbenzidine (TMB) for colorimetric measurement, utilizing a device with integrated reagent delivery and absorbance analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods are used to measure manganese in aqueous samples, then the measurement process is simple, but the presence of chlorine or chlorine-containing species leads to inaccurate results

Engineering Contradiction:
Improvemanganese measurement accuracyVSAvoidchlorine interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by adding a dechlorination reagent containing iron(II) and potassium iodide to the aqueous sample before the manganese measurement. This reagent reduces chlorine and chlorine-containing species to chloride ions, eliminating the harmful interference before it can affect the manganese detection accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary substance - the dechlorination reagent - that mediates between the harmful chlorine interference and the manganese measurement. The reagent contains iron(II) which acts as a reducing agent to convert chlorine to chloride, and potassium iodide which assists in the dechlorination process, thereby protecting the measurement from interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If some conventional methods are used, then the measurement process is available, but they are not environmentally friendly or compliant with regulatory guidelines

Engineering Contradiction:
Improveenvironmental complianceVSAvoidmethod availability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical parameters of the measurement system by using iron(II) and potassium iodide as dechlorination reagents instead of conventional chlorine-resistant methods. This parameter change enables environmental compliance while maintaining measurement reliability, as the new reagent system is both eco-friendly and regulatory-compliant.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a dechlorination reagent with iron(II) and potassium iodide is used, then chlorine interference is reduced, but the device complexity increases due to integrated reagent delivery and analysis systems

Engineering Contradiction:
Improvemanganese measurement accuracy in presence of chlorineVSAvoidintegrated reagent delivery and absorbance analysis system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated system: the dechlorination reagent delivery mechanism, the manganese oxidation step with TMB, and the absorbance analysis are combined into one unified measurement process. This integration, while increasing device complexity, ensures accurate manganese measurement in the presence of chlorine by automatically performing all necessary transformations and measurements in sequence.

Inventive Principle:
Principle #5Merging (Combining)

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 accurate and environmentally friendly measurement of manganese in the presence of chlorine, providing real-time data with minimal human intervention and compliance with regulatory standards.

Implementation Method 1

The aqueous sample is reduced using a dechlorination reagent. The dechlorination reagent contains iron(II) and potassium iodide.

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 2

Mn(IV) oxidizes the TMB, and the amount of manganese within the aqueous sample is determined by measuring an absorbance intensity at a wavelenght of the oxidized amount of TMB.

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP4396574B1Manganese detection
Publication Date: 2026.01.28 HACH
  • EP4396574B1 patent drawingFigure 1
  • EP4396574B1 patent drawingFigure 2
  • EP4396574B1 patent drawingFigure 3

AI summary

An embodiment of a method for measuring an amount of manganese in an aqueous sample includes: reducing, using a dechlorination reagent, wherein the dechlorination reagent comprises iron(ll) and potassium iodide; oxidizing, under an alkaline condition using sodium hydroxide, Mn(ll) to Mn(IV) in the aqueous sample, chelating, using etidronic acid (HEDP), Fe(ll) and Fe(lll) in the aqueous sample, oxidizing an amount of the colorimetric indicator 3, 3', 5,5'- tetramethylbenzidine (TMB) with Mn(IV); and measuring the amount of manganese within the aqueous sample, by measuring an absorbance intensity at a wavelength of the oxidized amount of 3,3',5,5'-tetramethylbenzidine (TMB). Other aspects are described and claimed.