ICP-MS Standard Solution Calibration for Metal Nanoparticle Sizing

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Solution Overview

Problem

Analyzing metal fine particles in liquids or gases using inductive coupling plasma mass spectrometry is challenging due to the difficulty in preparing standard solutions with known particle diameters, especially for elements like Au, and the inefficient analysis of metal fine particles in gas phases, where accurate control of particle diameter and number is hard to achieve.

Innovation Solution

A method involving a standard solution introduction apparatus with a syringe pump that supplies a standard solution at a flow rate of 3 µL/min or less directly to the nebulizer, allowing for 100% introduction into the plasma, enabling the calculation of particle diameter and concentration of metal fine particles without the need for standard metal fine particles, using a standard solution sensitivity value determined by signal intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If standard metal fine particles with known particle diameter are used for calibration, then particle diameter measurement is enabled, but preparation difficulty and cost increase significantly

Engineering Contradiction:
Improveparticle diameter measurementVSAvoidstandard solution preparation
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the need for physical standard metal fine particles with a virtual standard curve generated from theoretical calculations. Instead of using actual particle standards, the method calculates equivalent signal intensities based on metal content and creates a calibration curve that copies the measurement function without requiring difficult-to-obtain standard particles.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent introduces an intermediary calculation method that converts particle diameter measurements into metal content equivalents. By using the relationship between particle diameter, density, and metal content, the system mediates between the measurable signal intensity and the desired particle diameter information without requiring direct particle standards.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If metal fine particles in gas phase are analyzed, then analysis capability is expanded, but accurate control of particle diameter and number becomes difficult

Engineering Contradiction:
Improvegas phase analysis capabilityVSAvoidparticle diameter and number control
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the measurement parameter from direct particle diameter measurement to metal content measurement. By measuring the total metal content in the gas phase sample and using the calibration curve, the system can infer particle characteristics without requiring precise control or knowledge of individual particle diameters and numbers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical approach of directly measuring and controlling particle physical dimensions with a chemical/analytical approach. Instead of mechanically characterizing each particle, the system uses mass spectrometry to measure metal content and derives particle information from the calibrated relationship between metal content and particle properties.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If conventional calibration methods are used, then analysis of dissolved metal is achieved, but analysis of metal fine particles requires separate complex procedures

Engineering Contradiction:
Improvemetal concentration measurementVSAvoidanalysis procedure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a universal calibration curve that serves multiple functions: it can be used for both dissolved metal analysis and metal fine particle analysis. The single calibration curve based on metal content equivalents replaces the need for separate calibration procedures for different sample types, simplifying the overall analytical process while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 measurement of particle diameter and concentration of metal fine particles in both liquid and gas samples, ensuring efficient analysis by stabilizing signal intensity and maintaining high sensitivity, even at low flow rates, without the need for standard metal fine particles.

Implementation Method 1

a torch section for ionizing a sample by forming a plasma

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

atoms of a metal element contained in the sample solution are ionized

Methodology Applied
Scientific EffectIonization: Ionisation

Data Source

PatentEP3739329B1Method for analyzing metal fine particles, and inductive coupling plasma mass spectrometry method
Publication Date: 2023.10.04 IAS LIMITED
  • EP3739329B1 patent drawingFigure 1
  • EP3739329B1 patent drawingFigure 2
  • EP3739329B1 patent drawingFigure 3~4

AI summary

The present invention provides a method for analyzing a sample containing metal fine particles with an inductive coupling plasma mass spectrometer. The method enables analysis of the sample without the need of standard metal fine particles. Specifically, the present invention relates to a method for analyzing metal fine particles in liquid by use of an inductive coupling plasma mass spectrometer. In the method, the analysis apparatus is provided with a standard solution introduction apparatus including a standard solution storage unit for storing a standard solution containing a specific element in a known concentration, a syringe pump for suctioning and discharging the standard solution, and a solution introduction unit having a standard solution nebulizer and a standard solution spray chamber that are supplied with the standard solution, the standard solution is directly supplied to the standard solution nebulizer at a flow rate of 3 µL/min or less, and a particle diameter value of metal fine particles of a specific element is calculated based on a standard solution signal intensity obtained from a detector and a physical amount of an introduced specific element.