Ion Funnel Ion Trap for High-Sensitivity Mass Spectrometry
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Solution Overview
Problem
Current ion analysis technologies face challenges in efficiently guiding and focusing ions in the gas phase, particularly in transmitting ions between coupled stages at different gas pressures, which affects sensitivity and accuracy in ion separation and analysis.
Innovation Solution
The ion funnel ion trap (IFT) system, comprising an inlet portion that diverges ions, a trapping portion that accumulates and controls ion flow using electrostatic grids, and an outlet portion that converges and focuses ions, operates at varying pressures to enhance ion transmission and sensitivity by controlling dc- and rf-potentials independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ion transmission methods are used between coupled stages, then ion transmission is maintained, but ion guiding and focusing efficiency deteriorates, leading to reduced sensitivity and accuracy
Solution Approach 1:
The ion transmission system is divided into three distinct functional segments: an inlet portion with diverging electrodes to expand ion beams, a trapping portion with electrostatic grids to accumulate and control ion flow, and an outlet portion with converging electrodes to focus ions. This segmentation allows each portion to be optimized for its specific function, improving overall ion transmission efficiency and analysis precision.
Solution Approach 2:
The patent transitions from conventional linear ion transmission to a three-dimensional ion manipulation approach using electrostatic grids with multiple dimensions of control. The electrostatic grids create electric fields in multiple spatial dimensions, enabling precise control over ion trajectories, accumulation, and release in a manner that enhances both sensitivity and accuracy.
2Measurement precision
If ion accumulation is increased to enhance sensitivity, then signal-to-noise ratio improves, but ion transmission time and instrument duty cycle deteriorate
Solution Approach 1:
The trapping portion operates in periodic cycles, accumulating ions during one phase and releasing them in controlled bursts during another phase. This periodic operation allows significant ion accumulation to build up signal intensity while the rapid release mechanism maintains high instrument duty cycle by quickly resetting the trap for the next accumulation cycle.
Solution Approach 2:
Ions are accumulated in advance in the trapping portion before analysis, building up sufficient signal-to-noise ratio beforehand. The pre-accumulated ion packets are then rapidly transmitted to the analysis stage, allowing sensitive detection without compromising the instrument's ability to quickly process subsequent ion samples.
3Ease of operation
If electrostatic grids are added to control ion flow, then ion transmission control improves, but device complexity increases
Solution Approach 1:
The electrostatic grids in the trapping portion serve multiple functions simultaneously: they control ion entry from the inlet portion, accumulate ions during the trapping phase, and facilitate ion release to the outlet portion. This multi-functionality reduces the need for separate control mechanisms, managing device complexity while maintaining ease of ion flow control.
Solution Approach 2:
The patent combines the functions of ion guiding, focusing, and accumulation into an integrated trapping portion that merges several operations into a single structural unit. The electrostatic grids are positioned and configured to perform multiple control functions within one compact assembly, simplifying the overall device architecture while enhancing operational control.
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
The IFT system significantly improves ion analysis sensitivity and efficiency, achieving 10-30-fold gains in signal-to-noise ratio and increased ion packet charge density, enabling high-speed, high-resolution ion analysis with improved mass accuracy and instrument duty cycle.
Implementation Method 1
an inlet portion defined by electrodes that diverges ions in an ion beam introduced thereto to expand same
Implementation Method 2
a trapping portion defined by electrodes that operatively couple to the inlet portion and traps and accumulates a preselected quantity of ions received from the inlet portion. The trapping portion includes an electrostatic grid that controls entry of ions from the inlet portion
Implementation Method 3
Electrodes of the ion trap are equipped to include an rf-potential that is phase shifted 180 degrees from a subsequent electrode in the ion trap
Implementation Method 4
an outlet portion that is defined by electrodes that are operatively coupled to the trapping portion and serve to converge preselected ions released from the trapping portion
Implementation Method 5
The trapping portion includes an electrostatic grid that controls entry of ions from the inlet portion and one or more electrostatic grids that control outflow of a preselected quantity of ions accumulated in, or otherwise released from, the trapping portion
Data Source
AI summary
An ion funnel trap is described that includes a inlet portion, a trapping portion, and a outlet portion that couples, in normal operation, with an ion funnel. The ion trap operates efficiently at a pressure of ˜1 Torr and provides for: 1) removal of low mass-to-charge (m/z) ion species, 2) ion accumulation efficiency of up to 80%, 3) charge capacity of ˜10,000,000 elementary charges, 4) ion ejection time of 40 to 200 μs, and 5) optimized variable ion accumulation times. Ion accumulation with low concentration peptide mixtures has shown an increase in analyte signal-to-noise ratios (SNR) of a factor of 30, and a greater than 10-fold improvement in SNR for multiply charged analytes.