Mercury Sample Oxidation Control for Accurate ICP-MS Analysis
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Solution Overview
Problem
Existing mercury analysis methods, such as reduction vaporization atomic absorption, face challenges in achieving high accuracy due to sulfuric acid viscosity issues and mass interference with sulfur, particularly when using ICP-MS, and mercury recovery rates are compromised by the presence of reducing substances and organic matter.
Innovation Solution
A method involving a pretreatment step with an oxidizer to achieve an oxidation-reduction potential of +0.80 V or higher, followed by a quantitative or qualitative analysis while maintaining the oxidation state, using a flow analysis method with heat treatment, cooling, and gas-liquid separation to stabilize mercury as [HgCl2], [HgCl3]-, and [HgCl4]2-.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sulfuric acid is added in large amount for pretreatment before ICP-MS analysis, then mercury can be analyzed simultaneously with other metal elements, but sulfuric acid viscosity causes problems in spraying from nebulizer and mass interference occurs with other substances
Solution Approach 1:
The patent changes the chemical parameters of the sample solution by adjusting oxidation-reduction potential to +0.80V or higher through controlled addition of oxidizers (potassium permanganate, sodium hypochlorite, hydrogen peroxide) and acids (nitric acid, hydrochloric acid). This parameter change transforms mercury into stable oxidized forms that prevent volatilization and interference, enabling accurate ICP-MS analysis without the need for large amounts of sulfuric acid.
Solution Approach 2:
The patent introduces an intermediary oxidation state as a mediator between the sample and the analysis process. By maintaining mercury in a specific oxidized state (ORP ≥ +0.80V), the patent creates a stable intermediate form that prevents direct interference with the ICP-MS measurement, effectively mediating between the sample matrix and the detection system.
2Reliability
If conventional pretreatment with sulfuric acid, nitric acid, and potassium permanganate is carried out, then mercury can be oxidized to Hg2+ state, but the process is complex and requires multiple reagents
Solution Approach 1:
The patent creates a universal pretreatment condition that simultaneously achieves multiple objectives: oxidation of mercury to stable oxidized forms, prevention of volatilization, and preparation for ICP-MS analysis. By maintaining ORP at +0.80V or higher through controlled addition of oxidizers and acids, the patent establishes a multi-functional treatment state that simplifies the overall process while ensuring reliable mercury stabilization.
3Adaptability or versatility
If reducing substances and organic matter are present in the sample, then mercury analysis can be performed on real samples, but mercury recovery rate is compromised
Solution Approach 1:
The patent employs strong oxidizers (potassium permanganate, sodium hypochlorite, hydrogen peroxide) to accelerate the oxidation of mercury and other reducing substances in the sample. By maintaining oxidation-reduction potential at +0.80V or higher, the patent ensures complete oxidation of interfering substances and stabilization of mercury in oxidized forms, thereby achieving high recovery rates even in complex real samples containing reducing substances and organic matter.
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 high-accuracy analysis of mercury using ICP-MS by preventing volatilization and maintaining stable oxidation states, thereby improving recovery rates and reducing interference from reducing substances.
Implementation Method 1
a pretreatment step of adding an oxidizer to a sample containing mercury to prepare a sample solution so as to achieve an oxidation state in which an oxidation-reduction potential is not less than +0.80 V
Implementation Method 2
a heating step of carrying out a heat treatment with respect to the sample to which the oxidizer has been added
Implementation Method 3
a cooling step of cooling the sample which has been subjected to the heat treatment and which is transferred inside the tube
Implementation Method 4
a gas-liquid separation step of removing gas which is present in the tube after cooling
Data Source
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AI summary
For the purpose of providing an analysis method that makes it possible to use, for example, ICP-MS to analyze, with high accuracy, a sample containing mercury, a method for analyzing a sample containing mercury includes: a pretreatment step of adding an oxidizer to a sample containing mercury to prepare a sample solution so as to achieve an oxidation state in which an oxidation-reduction potential is not less than +0.80 V; and an analysis step of subjecting the sample solution which has been prepared in the pretreatment step to a quantitative analysis or a qualitative analysis while maintaining the oxidation state.