Ion Optical Potential Adjustment for Mass Spectrometer Adduct Removal
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Solution Overview
Problem
Mass spectrometers face challenges in efficiently removing unwanted adducts and loosely bound species from heavy analyte ions after in-source dissociation, as they retain excess kinetic energy, which can hinder ion transmission through the instrument.
Innovation Solution
Dynamic adjustment of offset electrical potentials in the ion optics near the ion inlet end of a mass spectrometer to compensate for the increased kinetic energy of heavy ions, allowing for efficient removal of solvent, salt, and surfactants without compromising ion transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If in-source dissociation is used to remove unwanted adducts from analyte ions, then the clarity of mass spectra is improved, but heavy ions retain excess kinetic energy that hinders transmission through the mass spectrometer
Solution Approach 1:
The patent applies dynamic adjustment of offset electrical potentials in ion optical elements to adaptively control ion kinetic energy. By continuously monitoring ion flux and adjusting potentials in real-time, the system optimizes both fragmentation effectiveness and transmission efficiency for heavy ions with varying kinetic energies
Solution Approach 2:
The patent changes electrical potential parameters in ion optical elements to compensate for excess kinetic energy. By adjusting the magnitude and timing of potential adjustments, the system removes unwanted adducts while maintaining transmission of heavy ions through the mass spectrometer
2Speed
If gas pressure is increased downstream from the voltage drop to slow ions, then ion velocity is reduced, but transmission of smaller and lighter ions is dramatically slowed
Solution Approach 1:
The patent applies different offset electrical potentials to different ion optical elements along the ion path. By localizing the kinetic energy compensation to specific regions rather than uniformly increasing gas pressure throughout, the system selectively manages heavy ion velocity without impeding lighter ion transmission
Solution Approach 2:
The patent uses offset electrical potentials as an intermediary mechanism to control ion kinetic energy, replacing the direct approach of increasing gas pressure. This intermediary method provides finer control over ion velocities and avoids the side effects of universal pressure increases
3Speed
If the length of the region following the voltage drop is increased to provide more collisions, then heavy ions are better decelerated, but the instrument size and complexity increase
Solution Approach 1:
The patent replaces the mechanical approach of extending the physical ion path length with an electrical field-based solution. By using offset electrical potentials in ion optical elements, the system achieves kinetic energy compensation without requiring additional physical space or extended instrument dimensions
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 effectively dislodges and removes adduct species from heavy ions while ensuring efficient transmission through the mass spectrometer, improving the clarity of mass spectra by reducing interference from unwanted species.
Implementation Method 1
a voltage drop between two ion optical elements accelerates the ions into or through an inert gas. Upon energetically colliding with the neutral gas molecules, a portion of the ions' kinetic energy, as generated by the acceleration, is taken up by energetically excited vibrational modes that ultimately dislodge the unwanted adducted and loosely bound species
Implementation Method 2
a difference between the third and second offset electrical potentials reduces a portion of the imparted kinetic energy of analyte ions passing into the third chamber from the second chamber
Data Source
AI summary
A mass spectrometry method comprises: generating ions; directing the ions through an ion optical component within a first chamber having a first vacuum pressure, the ion optical component maintained at a first electrical potential; transferring the ions through an ion guide within a second chamber having a second vacuum pressure less than the first vacuum pressure, the ion guide maintained at a second electrical potential, wherein a difference between the first and second potentials imparts kinetic energy that causes collision-induced ion fragmentation within the second chamber that removes adduct species; and transferring the ions into another ion guide within a third chamber having a third vacuum pressure less than the second vacuum pressure, the other ion guide maintained at a third electrical potential, wherein a difference between the third and second potentials reduces a portion of the imparted kinetic energy of the ions passing into the third chamber.