SP-ICP-MS Particle Sizing Using Mass Flux Calibration
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Solution Overview
Problem
Current methods for particle sizing and counting of inorganic nanoparticles, particularly anisotropic or isotropic polyelemental nanoparticles, face challenges such as poor image contrast, particle clustering, and inability to distinguish between elements or phases, leading to biased manual counting and inefficient automated sizing processes.
Innovation Solution
A single-particle inductively-coupled plasma mass spectrometry (SP-ICP-MS) method that provides a one-size-fits-all protocol for simultaneous sizing and counting of inorganic nanoparticles, independent of size, shape, and element, using intensity-versus-counts histograms, mass flux calibration, and geometry-based calculations to determine particle size and volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automated image processing techniques are used for particle sizing, then productivity is improved, but measurement precision deteriorates due to poor image contrast and particle clustering
Solution Approach 1:
The patent replaces optical microscopy-based automated image processing with inductively coupled plasma mass spectrometry (ICP-MS) detection. This substitution transitions from optical/mechanical image analysis to a mass-spectrometric approach that detects particles based on their mass signal, eliminating the fundamental limitations of image contrast and particle clustering that plague optical methods.
Solution Approach 2:
The patent changes the detection parameter from optical properties (image intensity, contrast) to mass-to-charge ratio detection. By measuring the mass signal of individual particles as they pass through the plasma, the system achieves both high throughput and high precision, as the mass signal is not affected by optical limitations such as poor contrast or particle aggregation.
2Measurement precision
If manual particle counting is used, then measurement precision is maintained, but productivity deteriorates due to time-consuming processes
Solution Approach 1:
The patent replaces manual visual counting with automated ICP-MS detection. The mass spectrometer automatically detects and counts individual particles based on their mass signal, eliminating the need for human operators while maintaining the precision of individual particle identification. This achieves both high accuracy and high throughput simultaneously.
3Loss of information
If traditional sizing methods are used, then element distinction capability is improved, but device complexity increases due to multiple analysis steps
Solution Approach 1:
The patent employs ICP-MS as a universal detection platform that simultaneously provides particle sizing, counting, and elemental composition analysis. The mass spectrometer inherently detects both the mass signal (for sizing) and the elemental fingerprint (for composition), eliminating the need for separate analysis steps and reducing overall system complexity while maintaining comprehensive information acquisition.
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 enables accurate and precise sizing and counting of thousands of nanoparticles in minutes, eliminating bias and providing a complete picture of particle distributions, including aggregates missed by traditional techniques, with excellent agreement to conventional sizing data.
Implementation Method 1
the inductively-coupled plasma mass spectrometer is configured to use an inductively-coupled plasma to atomize and ionize samples to be analyzed
Implementation Method 2
the inductively-coupled plasma mass spectrometer is configured to use an inductively-coupled plasma to atomize and ionize samples to be analyzed
Implementation Method 3
an inductively-coupled plasma mass spectrometer, comprising of a mass analyzer such as a quadrupole or time-of-flight tube and an ion detector such as an electron multiplier
Data Source
AI summary
The invention concerns a single-particle inductively-coupled plasma (ICP) mass spectrometry particle sizing and counting method comprising providing or receiving an intensity-versus-counts histogram of particles detected using an ICP mass spectrometer, the intensity representing particle detection and the count representing particle detection frequency; providing or receiving mass flux calibration data or calibration curve data relating a value of the intensity measurement or data of the ICP mass spectrometer to a mass of material detected per acquisition interval or dwell time; determining a particle mass of the particles detected using the mass flux calibration data or the at least one mass flux calibration curve data, determining a particle volume of the detected particles using the determined particle mass, and determining a particle size of the particles detected using the determined particle volume of the particles detected and a determined or attributed geometry or shape of the detected particles.