Linear Ion Trap Mass Spectrometer Multi-Stage Analysis
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Solution Overview
Problem
Current tandem mass spectrometry instruments face limitations in multi-stage analysis, ion density issues, and differences in fragment ion abundance ratios when using ion traps with electron bombardment ion sources, which restrict dynamic range and accuracy in identifying compounds.
Innovation Solution
A mass spectrometer combining a quadrupole mass filter with a linear ion trap, utilizing high-frequency and DC voltages to trap and expel ions efficiently, allowing for multi-stage tandem mass spectrometry with improved sensitivity and dynamic range, and maintaining compatibility with conventional mass spectrum retrieval databases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 3D quadrupole ion trap is used for tandem mass spectrometry, then multi-stage mass spectrometry capability is achieved, but ion space charge effects limit the number of ions allowed, reducing dynamic range
Solution Approach 1:
The patent transitions from a 3D quadrupole ion trap to a linear ion trap configuration. This dimensional change from three-dimensional to linear geometry increases the ion trap volume and reduces ion density, thereby minimizing space charge effects while maintaining multi-stage mass spectrometry capability. The linear arrangement allows for longer ion storage paths and higher ion capacity without compromising resolution.
2Duration of action of moving object
If a quadrupole ion trap is used with electron bombardment ion source, then ion storage time is extended for fragment ion generation, but fragment abundance ratios differ significantly from standard databases, reducing identification accuracy
Solution Approach 1:
The patent modifies the ion trap configuration and operational parameters to control ion storage time and fragmentation conditions. By adjusting the linear ion trap's electric field parameters and collision gas conditions, the system optimizes fragment ion generation while maintaining abundance ratios that are more consistent with standard databases, thereby improving compound identification accuracy.
3Power
If precursor ions are excited to sufficient kinetic energy in an ion trap, then collision dissociation efficiency is improved, but the lower mass limit of fragment product ions increases, reducing available mass range
Solution Approach 1:
The patent employs dynamic control of the linear ion trap's electric fields to optimize ion excitation and dissociation. By dynamically adjusting the radiofrequency and direct current voltages during the analysis, the system maintains sufficient kinetic energy for effective collision dissociation while minimizing the lower mass limit effect, thereby preserving a broader mass range for fragment product ions.
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
Enables high-sensitivity multi-stage tandem mass spectrometry with broader dynamic ranges and accurate identification of compounds, overcoming limitations of single quadrupole and ion trap mass spectrometers by efficiently managing ion density and fragment ion analysis.
Implementation Method 1
a quadrupole mass filter... configured to receive ions from an ion source upstream of the quadrupole mass filter
Implementation Method 2
a linear ion trap located downstream of the mass filter... configured to trap ions transmitted by the mass filter
Implementation Method 3
an ion detector disposed at a side of the linear ion trap, configured to receive ions extracted from the side outlet of the linear ion trap
Data Source
AI summary
A tandem mass spectrometer is provided in the present invention. The mass spectrometer includes an ion source, a quadrupole mass filter located at downstream side of the ion source, a linear ion trap disposed at downstream side of the mass filter and an ion detector placed on the side of the ion trap, all of which are placed in a vacuum environment. The instrument can obtain MS meeting the standard spectral library search criteria by the quadrupole mass filter cooperating with linear ion trap, realize any multi-stage MS under two modes of axial collision and resonance excitation, and predict and optimize the inflow amount and types of samples under the ion trap analysis mode by the quadrupole. A tandem MS analysis method is also provided, which can repeatedly provide precursor ion selection, ion acceleration, achieve high-energy collision dissociation, low product ion mass discrimination effect.