Hg Nanoparticle Soil Extraction for Size and Concentration Detection
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Solution Overview
Problem
Current methods are inadequate for simultaneously determining the particle size distribution and concentration of nanoparticulate mercury (Hg-NPs) in natural soils due to challenges in identifying and quantifying Hg-NPs in complex soil matrices, particularly at low ambient concentrations and with background interferences from heterogeneous soil components.
Innovation Solution
A method involving mixing a soil sample with a sodium pyrophosphate solution, followed by sequential vortex and shaking treatments, ultrasonic extraction, and subsequent analysis using single particle inductively coupled plasma-mass spectrometry (spICP-MS) to achieve simultaneous determination of particle size distribution and concentration of Hg-NPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmission electron microscope equipped with energy dispersive spectroscopy (TEM-EDS) is used to identify nanoparticles in soil, then information on size and chemical composition can be obtained, but it requires high mercury concentration and only provides qualitative information of local areas, unable to provide particle number and mass concentrations
Solution Approach 1:
The patent replaces the mechanical/optical imaging system of TEM-EDS with a mass spectrometry-based detection system (spICP-MS). Instead of using electron beams and detectors to image particles, the method uses inductively coupled plasma to ionize mercury atoms and mass spectrometry to detect and quantify them, enabling accurate measurement of particle number and mass concentrations without requiring high mercury concentrations or providing only local qualitative information.
2Measurement precision
If synchrotron-based X-ray absorption spectroscopy is used to identify speciation of mercury in soils, then speciation information can be obtained with high mercury concentration, but it fails to provide information about size distribution and concentrations of nanoparticulate mercury
Solution Approach 1:
The patent segments the detection process into two distinct measurement modes using spICP-MS: one for detecting particle number concentration and size distribution, and another for detecting total mercury concentration. This segmentation allows the method to provide comprehensive information including particle size distribution, particle number concentration, and mass concentration simultaneously, overcoming the limitation of X-ray absorption spectroscopy which only provides speciation information.
3Productivity
If conventional extraction methods are used for Hg-NPs in soil, then extraction can be performed, but Hg-NPs may undergo dissolution or aggregation, affecting determination accuracy
Solution Approach 1:
The patent changes the chemical parameters of the extraction system by using a specific reducing agent (sodium borohydride) and controlling pH conditions. These parameter changes create an extraction environment that prevents Hg-NP dissolution and aggregation, maintaining particle integrity while achieving efficient extraction. The controlled chemical parameters ensure both high productivity and reliability in Hg-NP determination.
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 method allows for accurate and simultaneous determination of Hg-NPs in natural soils, providing both mass and number concentrations, with a low limit of detection and wide applicability, suitable for environmental samples, while avoiding dissolution or aggregation of Hg-NPs.
Implementation Method 1
mixing a soil sample with a sodium pyrophosphate solution and subjecting the resulting mixture to an extraction to obtain a soil mixture
Implementation Method 2
the extraction includes an ultrasonic treatment and a second vortex treatment performed in sequence
Implementation Method 3
testing the supernatant using single particle inductively coupled plasma-mass spectrometry to simultaneously obtain the particle size distribution and concentration of nanoparticulate mercury
Implementation Method 4
single particle inductively coupled plasma-mass spectrometry
Implementation Method 5
leaving the soil mixture for a sedimentation and collecting the supernatant for testing
Data Source
AI summary
Disclosed is a method for simultaneous determination of particle size distribution, concentrations of nanoparticulate mercury (Hg-NPs) in natural soils. The method uses sodium pyrophosphate as the extractant, and allows quick extraction of Hg-NPs in the soil without dissolution or aggregation. In combination with spICP-MS determination, the method makes it possible to simultaneously determine the particle size distribution and concentration of Hg-NPs in the complex soil matrix, with accurate determination results.