TOF Ion Packet Concentration Switching to Prevent Detector Saturation

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Solution Overview

Problem

Existing tandem mass spectrometry methods face challenges in handling complex samples with large dynamic ranges, particularly in targeted and data-independent acquisition methods, leading to reduced sensitivity and saturation issues when using Zeno pulsing due to the need for millisecond delays in switching between pulsing modes.

Innovation Solution

A system and method for dynamically controlling an ion guide to switch between sequential (Zeno) and continuous pulsing modes based on previously measured ion intensity, allowing ion packets to be concentrated at a TOF mass analyzer without delays, thereby increasing dynamic range and preventing detector saturation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If Zeno pulsing mode is used to concentrate ion packets, then sensitivity is improved, but detector saturation occurs due to high ion intensity

Engineering Contradiction:

ImprovesensitivityVSAvoiddetector saturation

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system dynamically switches between Zeno pulsing mode and continuous mode based on real-time ion intensity measurements. When ion intensity exceeds a threshold indicating saturation risk, the system transitions from Zeno pulsing to continuous mode, and vice versa. This dynamic adaptation allows the system to maintain high sensitivity when needed while preventing detector saturation.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If Zeno pulsing mode is used to concentrate ion packets, then sensitivity is improved, but millisecond delays occur when switching between pulsing modes

Engineering Contradiction:

ImprovesensitivityVSAvoidswitching delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary ion intensity measurements during the ion transfer period before the TOF extraction pulse. Based on these preliminary measurements, the decision to switch between Zeno pulsing and continuous modes is made in advance, allowing the new mode to be ready and active by the time the next ion packet arrives. This eliminates switching delays by preparing the mode change beforehand.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous operation by overlapping the mode decision and switching process with the ion transfer time. The ion intensity measurement and mode selection occur during the period when ions are being transferred, so the mode switch is prepared and executed without interrupting the continuous flow of ion analysis.

Inventive Principle:

Principle #20Continuity of useful action

3Object-affected harmful factors

If continuous mode is used instead of Zeno pulsing, then detector saturation is prevented, but sensitivity decreases

Engineering Contradiction:

Improvedetector saturationVSAvoidsensitivity

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The system changes the operational parameter (pulsing mode) based on ion intensity conditions. When ion intensity is low, Zeno pulsing mode is used to concentrate ions and improve sensitivity. When ion intensity becomes high and approaches saturation levels, the system switches to continuous mode to prevent saturation. This parameter change allows the system to optimize for sensitivity when safe and prevent saturation when necessary.

Inventive Principle:

Principle #35Parameter changes

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 enhances sensitivity and prevents saturation by dynamically adjusting pulsing modes, maintaining mass accuracy and resolution, and enabling effective quantitation in targeted acquisition methods.

Implementation Method 1

the ion guide is instructed to eject the product ions using a sequential or Zeno pulsing mode where there is a sequential ejection of the product ions from the ion guide to the TOF mass analyzer according to the m/z values of the product ions to provide for arrival of product ions of substantially all released m/z values within the extraction region at substantially the same time

Methodology Applied

Scientific EffectIon guide sequential ejection (Zeno pulsing):

Implementation Method 2

a TOF mass analyzer downstream of the ion guide to receive the product ions ejected from the ion guide into an extraction region of the TOF mass analyzer along the guide axis and measure the intensity of at least one known product ion

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Data Source

PatentUS20250299942A1Dynamically Concentrating Ion Packets in the Extraction Region of a TOF Mass Analyzer in Targeted Acquisition

Publication Date: 2025.09.25 DH TECH DEVMENT PTE

AI summary

Systems and methods are disclosed for dynamically switching an ion guide and a TOF mass analyzer between concentrating or not concentrating ions in a targeted acquisition. Product ions are ejected from the ion guide into the TOF mass analyzer and the intensity of a known product ion is measured at two or more time steps. The ion guide initially ejects product ions using a sequential or Zeno pulsing mode that concentrates product ions with different m/z values within the TOF mass analyzer at the same time. If the intensity of the product ion is increasing and greater than a threshold intensity, the ion guide switches to a continuous or normal pulsing mode that does not concentrate ions with different m/z values in the TOF mass analyzer at the same time. Similarly, if the intensity decreases below a threshold in continuous mode, the ion guide switches back to sequential mode.