Tandem Ionizer Mass Spectrometer Source Design
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Solution Overview
Problem
Current mass spectrometry (MS) devices have low efficiency due to incomplete ionization of analytes, failure to detect electrically-neutral analytes, and space charge repulsion, resulting in a small fraction of sample ions reaching the detector.
Innovation Solution
The proposed solution involves an LC-MS system with an electrospray needle and a second ionizer within a vacuum chamber, where a gas is used to nebulize fluid and assist in ionization, and a heating element to desolvate the mobile phase, along with a capillary to increase analyte density and a charge blocking grid to selectively pass neutral analytes, enhancing ionization and detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single ionizer is used in known MS devices, then the device complexity is low, but the ionization completeness is poor and detection efficiency is low
Solution Approach 1:
The single ionizer is divided into two separate ionizers: a first ionizer that performs initial ionization and a second ionizer that performs secondary ionization on neutral analytes. This segmentation allows each ionizer to specialize in different ionization tasks, improving overall ionization completeness and detection efficiency while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent introduces a temporal dimension to the ionization process by sequencing the operation of two ionizers. The first ionizer operates initially, then the second ionizer operates subsequently on the remaining neutral analytes. This dimensional expansion from single-stage to multi-stage ionization resolves the contradiction by adding process depth without excessive complexity.
2Quantity of substance
If electrospray ionization is used, then ionization occurs, but space charge repulsion causes rarefaction and decreases sample density
Solution Approach 1:
The first ionizer performs preliminary ionization to create charged analytes before the second ionizer operates. By pre-ionizing a portion of the analytes, the system reduces the overall charge density that would otherwise cause severe space charge repulsion, thereby maintaining higher sample density while still achieving complete ionization through the subsequent second ionization stage.
Solution Approach 2:
The patent implements continuous ionization action through two sequential ionizers rather than a single continuous high-charge process. The first ionizer continuously produces ions, and the second ionizer continuously ionizes remaining neutrals, maintaining a more stable charge distribution that reduces rarefaction effects while sustaining high ionization efficiency.
3Reliability
If neutral analytes are present in the sample, then the sample composition is complete, but the detector cannot detect electrically-neutral analytes
Solution Approach 1:
The detection system is segmented into two functional paths: the first ionizer handles charged analyte detection, while the second ionizer specifically addresses neutral analyte conversion to charged species. This segmentation ensures complete detection coverage for both charged and neutral analytes without requiring a fundamentally different detection mechanism, thereby improving reliability while controlling complexity.
Solution Approach 2:
The second ionizer acts as an intermediary between neutral analytes and the detector. It converts electrically-neutral analytes into charged ions that can then be detected by the existing mass spectrometer detector, thereby extending detection coverage to neutral species without requiring a new type of detector and maintaining acceptable system complexity.
4Productivity
If incomplete ionization occurs, then the ion source operation is simple, but the percentage of analytes reaching the detector is small
Solution Approach 1:
The ionization process is segmented into two distinct stages performed by separate ionizers. The first ionizer performs initial ionization on a portion of analytes, and the second ionizer performs secondary ionization on remaining neutral analytes. This segmentation ensures near-complete ionization of all analyte types, dramatically increasing the percentage of analytes that reach the detector while keeping each individual ionization stage relatively simple.
Solution Approach 2:
Instead of relying on a single ionizer to achieve complete ionization, the patent applies partial ionization twice through two sequential ionizers. The first ionizer ionizes some analytes, and the second ionizer ionizes the remaining portion, collectively achieving excessive ionization coverage that ensures virtually all analytes are ionized and detectable, thereby maximizing detection rate.
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 increases the ion current and sensitivity, allowing a higher percentage of analytes to be detected, reducing noise, and enabling lower detection levels by improving ionization and desolvation processes.
Implementation Method 1
The analytes are provided to an ion source of a mass spectrometer (MS)... Liquid output by the LC device is nebulized to form droplets
Implementation Method 2
Ideally, the mobile phase is removed, leaving the analytes
Implementation Method 3
Charged analytes are then provided to a mass analyzer for spectroscopic analysis
Implementation Method 4
Charged analytes are then provided to a mass analyzer for spectroscopic analysis
Data Source
AI summary
An ion source a first ionizer comprising: an electrospray needle comprising a tip; and a conduit disposed annularly about the needle and configured to pass an inert gas in proximity of the tip to nebulize a fluid emerging from the tip, the nebulized fluid comprising analytes and a mobile phase. The ion source comprises a capillary in tandem with the first ionizer and configured to receive the droplets; a heater configured to heat the capillary to a temperature at which mobile phase vaporizes; and a second ionizer in tandem with the capillary and configured to receive the vaporized mobile phase and the analytes. A method is also described.