Water-Soluble Thioether Nitrate Detection Without Shaking

Solution Overview

Problem

Current methods for measuring aqueous nitrate concentration, such as colorimetric tests, face challenges including toxicity of reagents like cadmium, variability due to shaking requirements, and limitations in using solid reagents in portable testing equipment, which restricts the detection range and sensitivity.

Innovation Solution

A method involving a water-soluble thioether compound with a chromophore group and a water-soluble catalyst, such as MoO2Cl2 with a hydrophilic phosphine group, undergoes sulfoxidation in the presence of nitrate, causing a color change measurable in the visible light spectrum, allowing for correlation of nitrate concentration without toxic metals and shaking, and can be used in portable analyzers with all components being water-soluble.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cadmium is used as a reductant in nitrate testing, then nitrate can be reduced to nitrite for analysis, but toxic metal contamination and health hazards occur

Engineering Contradiction:

Improvenitrate reduction efficiencyVSAvoidtoxicity of reagents

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the toxic cadmium reagent from the testing system while maintaining the nitrate reduction function through alternative means. The solid cadmium reagent is replaced with a cadmium-free chemical system that achieves the same analytical purpose without introducing toxic metal contamination into water samples.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful effect of requiring shaking (which causes variability) into a beneficial feature by developing a method that works without shaking. The new approach transforms the previously harmful mechanical disturbance into an unnecessary step, thereby eliminating variability while maintaining effective nitrate reduction and detection.

Inventive Principle:

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

2Reliability

If shaking is required in cadmium-based nitrate reduction systems, then nitrate can be reduced to nitrite, but variability in testing results occurs due to surface reaction disruption

Engineering Contradiction:

Improvenitrate reduction capabilityVSAvoidtesting variability

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of requiring shaking (which causes variability) into a beneficial feature by developing a method that works without shaking. The new approach transforms the previously harmful mechanical disturbance into an unnecessary step, thereby eliminating variability while maintaining effective nitrate reduction and detection.

Inventive Principle:

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

3Reliability

If solid reagents are used in nitrate testing, then the reaction can proceed effectively, but the reagents cannot be deposited on test elements for portable testing

Engineering Contradiction:

Improvereaction effectivenessVSAvoidportability of testing equipment

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the physical state parameter of the reagents from solid to soluble form. The new method employs water-soluble reagents that can be dissolved in the test sample, allowing them to be deposited on portable test elements while maintaining effective chemical reactions for nitrate detection in field testing conditions.

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If water-soluble reagents are used in portable analyzers, then portability and ease of use improve, but sensitivity and detection range may be limited

Engineering Contradiction:

Improveportability of testing systemVSAvoiddetection sensitivity

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the physical state parameter of the reagents from solid to soluble form. The new method employs water-soluble reagents that can be dissolved in the test sample, allowing them to be deposited on portable test elements while maintaining effective chemical reactions for nitrate detection in field testing conditions.

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 eliminates toxic metals, reduces variability, and enables accurate nitrate detection between 0 and 15 ppmw, offering improved sensitivity and portability by using water-soluble reagents and catalysts deposited on test elements for use in portable analysis systems.

Implementation Method 1

The sulfoxidation of thioethers with nitrate as the oxidant and a homogeneous Mo/Cu(II) co-catalyst system has been reported as a pathway to sulfoxides in organic solvent such as acetonitrile

Methodology Applied

Scientific EffectSulfoxidation: Oxidation

Implementation Method 2

measuring a color change, and correlating the color change to nitrate concentration

Methodology Applied

Scientific EffectColor change: Photochromism

Implementation Method 3

The initial color wavelength of the hydrophilic chromophore group may, for example, be between 500 and 700 nm

Methodology Applied

Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Data Source

PatentUS10203316B2Colorimetric determination of aqueous nitrate concentration

Publication Date: 2019.02.12 HACH

AI summary

A method of measuring nitrate concentration in an aqueous sample include mixing the aqueous sample with a water-soluble thioether compound including a chromophore group in the presence of a water soluble catalyst; measuring a color change, and correlating the color change to nitrate concentration.