ICP-MS Sample Introduction Device with Water-Containing Gas
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Solution Overview
Problem
Inductively coupled plasma mass spectrometers (ICP-MS) face inefficiencies in sample introduction and interference from high ionization potential elements, leading to the generation of interfering molecule ions under low-temperature plasma conditions, especially when using desolvated-sample introduction devices.
Innovation Solution
A method and device that introduce a sample gas with desolvated sample mist and a water-containing carrier gas to the plasma, reducing plasma temperature and inhibiting the generation of interfering molecule ions by adding a water-containing gas to the sample introduction path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a desolvated-sample introduction device is used to reduce sample mist particle size and enhance sample introduction efficiency, then sample introduction efficiency is improved, but interfering molecule ions are generated under low-temperature plasma conditions
Solution Approach 1:
The invention changes the temperature parameter of the plasma from high temperature to low temperature conditions. By operating the plasma at lower temperatures, the ionization of elements with high ionization potential is suppressed, thereby reducing the generation of interfering molecule ions while maintaining effective sample introduction through desolvation
Solution Approach 2:
The invention applies different temperature conditions to different aspects of the analysis: low temperature plasma is used specifically for analyzing elements with high ionization potential to suppress interfering molecule ion formation, while the desolvation process maintains efficient sample introduction. This localized application of temperature control resolves the contradiction between sample introduction efficiency and interfering ion generation
2Object-generated harmful factors
If plasma temperature is reduced to inhibit ionization of elements with high ionization potential, then interfering molecule ion generation is reduced, but sample introduction efficiency decreases
Solution Approach 1:
The invention performs desolvation of the sample mist before introducing it to the low-temperature plasma. By removing the solvent in advance through heating and evaporation, the sample particles are concentrated and dried, which compensates for the reduced ionization efficiency at lower plasma temperatures and maintains overall sample introduction efficiency
Solution Approach 2:
The invention changes the plasma temperature parameter to low temperature conditions specifically suited for analyzing elements with high ionization potential. This parameter change suppresses the ionization of interfering elements while the desolvation process ensures adequate sample delivery efficiency is maintained
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 enhances sample introduction efficiency and reduces interfering molecule ion generation, allowing for more accurate analysis of elements like Fe by maintaining a low-temperature plasma condition and minimizing ionization of elements with high ionization potential.
Implementation Method 1
supplies radio frequency power to a loading coil placed on a plasma torch to generate inductively coupled plasma, sprays an aerosolized sample solution to the center portion of the plasma, and ionizes an element contained in the sample
Implementation Method 2
sample mist generated by a nebulizer is heated in a heating chamber, a solvent in the sample mist is evaporated to reduce the sample mist particle sizes
Implementation Method 3
The vapor of the solvent evaporated by the heating chamber is cooled to condense the solvent and can be discharged as drainage
Implementation Method 4
supplies radio frequency power to a loading coil placed on a plasma torch to generate inductively coupled plasma
Data Source
AI summary
A desolvation unit performs desolvation by heating after a sample solution is turned to sample mist by a nebulizer. A sample gas that contains the desolvated sample mist and a carrier gas is introduced through a sample introduction tube to a plasma torch. An addition unit for adding, to the sample introduction tube, a water-containing gas is provided. The addition unit includes a container that contains ultrapure water, a gas tube for introducing the carrier gas into the ultrapure water to cause bubbling, and a gas tube for adding the water-containing gas, to the sample introduction tube. The plasma torch generates an inductively coupled plasma under the condition that supplied power is set to a range of 550 W to 700 W. Generation of interfering molecule ions due to an element having a high ionization potential is inhibited when an element in a sample ionized by the plasma is analyzed.