Lead(0) Digestion via Copper(II) Acetate for Colorimetric Detection

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Solution Overview

Problem

Traditional methods for measuring lead in aqueous samples are unreliable for detecting low levels and often require hazardous materials, making them unsuitable for field use and posing disposal challenges.

Innovation Solution

A method involving the digestion of lead(0) to lead(II) using copper(II) acetate, followed by chelation of unreacted copper(II) with an organosulfur compound and measurement with a colorimetric indicator, such as xylenol orange tetrasodium salt, to detect lead(II) concentrations through colorimetric changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional methods for measuring lead in aqueous samples are used, then lead detection is possible, but the methods are unreliable for detecting low levels and require hazardous materials

Engineering Contradiction:
Improvelead detection accuracyVSAvoidhazardous materials
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces copper(II) acetate as an intermediary substance that facilitates the conversion of lead(0) to lead(II) through a controlled chemical reaction. This intermediary enables the measurement process to proceed with safer, non-hazardous materials while maintaining detection accuracy for low lead levels.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical state of lead from lead(0) metal to lead(II) ion through oxidation, and subsequently changes the form of detection by using colorimetric indicators that respond to lead(II) ions. This parameter transformation enables reliable detection at low concentrations without requiring hazardous reagents.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional lead measurement methods are used, then lead detection is possible, but they pose disposal challenges and are unsuitable for field use

Engineering Contradiction:
Improvelead detection reliabilityVSAvoidfield suitability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs disposable test strips or measurement units that contain all necessary reagents (copper(II) acetate, organosulfur compounds, colorimetric indicators) in a pre-packaged format. These single-use units eliminate the need for complex disposal procedures and hazardous material handling, making them ideal for field deployment while maintaining reliable lead detection.

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

Solution Approach 2:

The patent extracts and eliminates hazardous materials from the measurement process by replacing them with safe, environmentally benign substances. The method removes the need for dangerous reagents while preserving the core detection function, thereby enabling field use and simplifying disposal.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If copper(II) acetate is added to digest lead(0), then lead(II) is formed for measurement, but unreacted copper(II) may interfere with detection

Engineering Contradiction:
Improvelead(II) concentration measurementVSAvoidunreacted copper(II) interference
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent introduces organosulfur compounds (such as thiourea or its derivatives) as intermediary chelating agents that selectively bind to copper(II) ions. These intermediaries form stable complexes with unreacted copper(II), preventing it from interfering with the colorimetric detection of lead(II) while allowing the lead measurement to proceed accurately.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful presence of unreacted copper(II) into a beneficial outcome by using it to form colored complexes with organosulfur compounds. This transformation allows the copper to be masked and eliminated from the detection pathway, turning what would be an interference into a controlled chemical reaction that protects the lead measurement.

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

This approach allows for accurate and safe measurement of lead concentrations without hazardous materials, enabling reliable detection in both laboratory and field settings, reducing time and environmental impact.

Implementation Method 1

adding a copper(II) acetate material to the aqueous sample in the reaction vessel; chelating unreacted copper(II) material by introduction of an organosulfur compound

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Implementation Method 2

chelating unreacted copper(II) material by introduction of an organosulfur compound to the aqueous sample in the reaction vessel

Methodology Applied
Scientific EffectChelation: Chemical Bonding

Implementation Method 3

adding a colorimetric indicator to the aqueous sample in the reaction vessel; measuring a concentration of lead(II) in the aqueous sample by measuring a colorimetric change of the aqueous sample caused by a reaction of lead(II) within the aqueous sample with the colorimetric indicator

Methodology Applied
Scientific EffectColorimetric detection: Absorption Spectroscopy

Data Source

PatentEP3877761B1Digestion of lead(0) and subsequent colorimetric detection of lead (II)
Publication Date: 2023.11.08 HACH
  • EP3877761B1 patent drawingFigure 1
  • EP3877761B1 patent drawingFigure 2
  • EP3877761B1 patent drawingFigure 3

AI summary

An embodiment provides a method for measuring a concentration of lead(O) in an aqueous sample, including: introducing an aqueous sample to a reaction vessel; adding a copper(II) acetate material to the aqueous sample in the reaction vessel; chelating unreacted copper(II) material by introduction of an organosulfur compound to the aqueous sample in the reaction vessel; adding a colorimetric indicator to the aqueous sample in the reaction vessel; and measuring a concentration of lead(II) in the aqueous sample by measuring a colorimetric change of the aqueous sample caused by a reaction of lead(II) within the aqueous sample with the colorimetric indicator. Other aspects are described and claimed.