Mass Spectrometer Charging Location Identification
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Solution Overview
Problem
Mass spectrometers face challenges in identifying the specific location of charging within the instrument, which leads to reduced sensitivity due to contamination and aberrations in the electrical field, making it difficult to diagnose and correct the issue precisely.
Innovation Solution
A method involving the directional switching of ion polarity along the ion path, using both positive and negative ions to measure intensity changes, allowing for the identification of charging locations by comparing pre- and post-discharge ion intensities across multiple intermediate points, thereby pinpointing affected ion transfer optic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarity switching is used to diagnose charging, then the presence of contamination can be detected, but the specific location of charging cannot be identified
Solution Approach 1:
The ion path is divided into multiple segments by introducing intermediate locations where blocking potentials can be applied. This segmentation allows the diagnostic process to isolate and identify charging at specific locations along the ion path, transforming a global diagnostic approach into a localized one.
Solution Approach 2:
Blocking potentials are introduced as intermediary elements at intermediate locations along the ion path. These blocking potentials act as controllable barriers that can be applied selectively to different segments, enabling the diagnostic process to probe specific regions and identify where charging occurs.
2Reliability
If atmospheric ionization source orifices are increased to improve sensitivity, then instrument sensitivity increases, but the probability of contaminants entering increases
Solution Approach 1:
The patent implements a feedback mechanism where the diagnostic process continuously monitors ion transmission and identifies charging locations. This feedback loop allows operators to detect and address contamination issues promptly, maintaining high sensitivity while managing the increased risk from larger orifices.
Solution Approach 2:
The diagnostic method enables preliminary identification of charging problems before they significantly degrade performance. By regularly applying blocking potentials at intermediate locations and monitoring ion transmission, the system can detect contamination early and schedule maintenance before sensitivity is severely impacted.
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 effectively localizes charging within the mass spectrometer, enabling precise identification and corrective action, such as cleaning, to restore instrument sensitivity by determining the specific ion optic devices experiencing contamination.
Implementation Method 1
the rapid neutralization of positively charged ion transfer optic surfaces by the impingement thereon of negative ions
Implementation Method 2
the application of oscillatory and/or static voltages to the various ion transfer optic devices (e.g., radio-frequency multipoles, stacked-ring ion guides, and electrostatic lenses) to establish electric fields that radially confine the ions to a central ion path
Data Source
AI summary
A method is described for identifying the occurrence and location of charging of ion optic devices arranged along the ion path of a mass spectrometer. The method includes repeatedly performing a sequence of introducing a beam of discharge ions to a location on the ion path, and subsequently measuring the intensities of opposite-polarity sample ions delivered to a mass analyzer, with the discharge ions being delivered to a location further downstream in the ion path at each successive sequence.