Colorimetric Analysis Using Food Dye Reagent

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Solution Overview

Problem

Existing methods for measuring free chlorine in water are plagued by health hazards from reagents like DPD and methyl orange, inefficient reagent use, and water conservation issues due to reagent discharge, with complex and costly apparatus required for separate reagents.

Innovation Solution

A colorimetric method using FDA-approved food dyes like Brilliant Blue FCF as redox indicators, which are safe for water reuse and minimize reagent consumption, allowing for accurate free chlorine measurement over a wide range without sample dilution, using a single reagent system with a control algorithm to regulate reagent volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If DPD reagent is used for free chlorine measurement, then measurement sensitivity is improved, but health safety deteriorates due to toxicity and skin absorption risks

Engineering Contradiction:
Improvemeasurement sensitivityVSAvoidhealth safety
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces toxic DPD reagent with a safe, biodegradable food dye ( Brilliant Blue FCF) that serves as a single-use colorimetric indicator. The food dye is added to the water sample, reacts with free chlorine to change color, and the resulting mixture can be safely discharged or reused, eliminating health hazards associated with DPD disposal and handling

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If multiple separate reagents are used for analysis, then measurement accuracy is improved, but device complexity increases due to multiple reservoirs and dispensing systems

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidapparatus complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple reagent functions into a single food dye reagent solution. The Brilliant Blue FCF food dye serves simultaneously as the colorimetric indicator, the reaction substrate for free chlorine detection, and the safe disposal medium. This eliminates the need for separate DPD reservoir, buffer solutions, and multiple dispensing systems required by conventional methods

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The food dye reagent performs multiple functions: it acts as a redox indicator that changes color upon reaction with free chlorine, provides a measurable absorbance signal for quantification, and serves as a safe carrier that allows the entire reagent-sample mixture to be discharged into the water body without harm, thereby replacing multiple specialized reagents with one universal solution

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If conventional reagents are discharged into water, then measurement process is simplified, but water conservation deteriorates due to significant water loss over time

Engineering Contradiction:
Improveprocess simplicityVSAvoidwater loss
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

The patent converts the previously harmful discharge of toxic reagent-sample mixtures into a beneficial process by using a food-safe dye. The reacted mixture containing Brilliant Blue FCF and its oxidized products is non-toxic and can be safely returned to the water body, transforming what was previously environmental pollution into a harmless or even beneficial addition to the water system

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

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 method provides safe, efficient, and economical measurement of free chlorine, enabling water reuse and reducing reagent waste, with the ability to accurately measure across a broad concentration range without the need for dilution, using a single reagent system that is insensitive to calcium and alkalinity.

Implementation Method 1

a food dye, wherein the oxidising agent undergoes a reaction with said food dye

Methodology Applied
Scientific EffectRedox reaction: Redox Reactions

Data Source

PatentEP2567215B1Colorimetric analytical method
Publication Date: 2018.03.21 WATERCO
  • EP2567215B1 patent drawingFigure 1
  • EP2567215B1 patent drawingFigure 2
  • EP2567215B1 patent drawingFigure 3

AI summary

The invention provides a single colorimetric reagent for the measurement of oxidising agents such as free chlorine in a liquid sample which contains a food dye, whereby the oxidising agent undergoes a reaction with said food dye. A preferred food dye is Brilliant Blue FCF. There is also provided a control system for regulating the volume of reagent added to a fixed volume of sample according to a control algorithm to give a chosen excess of a reagent compound beyond that required to stoichiometrically react with the target analyte in the sample. Also disclosed are single reagents for colorimetric determination of total alkalinity and calcium hardness.