ICP-MS Electrode Voltage Shifting for Ion Sensitivity
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Solution Overview
Problem
In ICP-MS systems, the arrangement of particle passage ports on different axes to remove interfering particles can lead to reduced detection sensitivity of target ions, as it may prevent target ions from passing through, causing a decrease in the total amount of ions fed to the detector.
Innovation Solution
A mass spectrometer configuration with an ion source, sampling cone, collision cell, mass separation device, detector, and control device that sets electrode voltages based on the mass-to-charge ratio of target ions, using a predetermined gas to separate target ions from interfering particles, and an axis-shifting optical system to deflect ions while preventing neutral particles from entering the mass separation device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If particle passage ports are arranged on different axes to remove interfering particles, then interfering particles are removed, but target ions may be prevented from passing through, causing decreased detection sensitivity
Solution Approach 1:
The patent applies dynamics by making the electrode voltages adjustable and changeable based on operating conditions. The control device dynamically adjusts the voltages of the first and second electrodes to optimize ion transmission while removing interfering particles, allowing the system to adapt between different operational modes (with or without collision cell gas) to maintain detection sensitivity.
Solution Approach 2:
The patent changes the electrical parameter (electrode voltage) to control ion trajectory and transmission. By adjusting the electrode voltages based on whether collision cell gas is present and on the mass-to-charge ratio of target ions, the system optimizes the balance between removing interfering particles and maintaining target ion transmission efficiency.
2Reliability
If collision cell gas is used to separate target ions from interfering particles, then particle separation is improved, but electrode voltage settings become complex and require optimization
Solution Approach 1:
The control device implements feedback by automatically adjusting electrode voltages based on detected ion signals and mass-to-charge ratio information. The system monitors the ion transmission and interference levels, then adjusts the electrode voltages to optimize separation performance, reducing the need for manual optimization and complex voltage setting procedures.
Solution Approach 2:
The system performs self-service by automatically optimizing its own electrode voltage settings based on the presence of collision cell gas and the characteristics of target ions. The control device autonomously adjusts the voltages to maintain optimal separation and transmission conditions without requiring extensive manual intervention or complex external optimization procedures.
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 configuration enhances the detection sensitivity of target ions by ensuring that only target ions pass through the mass separation device, while interfering particles are effectively removed, thereby improving the overall detection efficiency.
Implementation Method 1
an ion source that ionizes a sample
Implementation Method 2
a mass separation device that is provided on a second axis parallel to the first axis and separates ions on a mass-to-charge ratio basis
Implementation Method 3
a first electrode having a particle passage port provided on the first axis between the cell and the mass separation device, and a second electrode having a particle passage port provided on the second axis between the first electrode and the mass separation device
Data Source
AI summary
An ICP-MS includes a control device, a collision cell and a first electrode that are provided on an optical axis of plasma, and a second electrode, a mass separation device, and a detector that are provided on a detection axis. The control device sets, as an axis-shifting voltage to be applied to each electrode of the first electrode and the second electrode in a gas-present mode, the voltage obtained by adding an offset determined according to a mass-to-charge ratio of a target ion to an initial voltage in a gasless mode.