Time of Flight Mass Analyzer Duty Cycle Optimization

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Solution Overview

Problem

Conventional orthogonal acceleration Time of Flight mass analyzers have a limited duty cycle, typically around 20-25%, with lower efficiency for ions with lower mass to charge ratios, and existing methods to enhance duty cycle are only effective for narrow ranges of mass to charge ratios, resulting in reduced sampling efficiency for a wide range of ions.

Innovation Solution

A Time of Flight mass analyzer with a control device that energizes the orthogonal acceleration electrode at multiple predetermined times after the release of ion packets, allowing for increased duty cycle across a wide range of mass to charge ratios by optimizing the timing of orthogonal acceleration pulses relative to ion packet releases from an ion trap or ion guide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single orthogonal acceleration pulse is applied to synchronize with ion packet release, then the duty cycle for ions of a specific mass to charge ratio is increased to near 100%, but the sampling efficiency for ions with other mass to charge ratios drops to zero or substantially lower

Engineering Contradiction:

Improveduty cycle for specific mass to charge ratioVSAvoidsampling efficiency across mass to charge ratio range

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The single orthogonal acceleration pulse is segmented into multiple pulses applied at different delay times. Each pulse is optimized to sample ions with different mass to charge ratios, thereby segmenting the sampling task across multiple temporal events rather than relying on a single synchronized pulse.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple orthogonal acceleration pulses are applied periodically at predetermined delay times after ion packet release. This periodic action with varying delay times allows the system to sample different ion populations systematically, converting a single-point synchronization into a multi-point periodic sampling strategy.

Inventive Principle:

Principle #19Periodic action

2Productivity

If the orthogonal acceleration electrode is energized at multiple predetermined times after ion packet release, then the duty cycle is enhanced across a wide mass to charge ratio range, but the device complexity increases

Engineering Contradiction:

Improveduty cycle across mass to charge ratio rangeVSAvoidcontrol device complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The control device is pre-programmed with predetermined delay times for energizing the orthogonal acceleration electrode. These delay times are calculated in advance based on the relationship between flight time, drift region length, and mass to charge ratio, allowing the system to execute complex multi-pulse sequences without real-time computational complexity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses the inherent flight time characteristics of ions through the drift region to automatically determine optimal sampling times. By measuring or calculating the flight time for different mass to charge ratios, the system self-generates the timing sequence for multiple acceleration pulses without requiring external complex control mechanisms.

Inventive Principle:

Principle #25Self-service

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 significantly enhances the duty cycle to near 100% for ions of interest and maintains high efficiency across a wide mass to charge ratio range, improving overall sampling efficiency and ion detection intensity.

Implementation Method 1

An orthogonal acceleration electric field is periodically applied across the orthogonal acceleration region in order to orthogonally accelerate ions into the drift region of the Time of Flight mass analyser

Methodology Applied

Scientific EffectOrthogonal acceleration: Electrostatics

Implementation Method 2

orthogonal acceleration Time of Flight mass analyser

Methodology Applied

Scientific EffectTime of flight mass analysis: Time of Flight

Data Source

PatentUS8183524B2Mass spectrometer having time of flight mass analyser

Publication Date: 2012.05.22 MICROMASS UK LTD

AI summary

A mass spectrometer is disclosed comprising an orthogonal acceleration Time of Flight mass analyser. A pulse or packet of ions is released either from an ion trap or alternatively from a travelling wave ion guide arranged upstream of an orthogonal acceleration electrode which forms part of the Time of Flight mass analyser. Ions in the pulse or packet or ions which is released become temporally dispersed and the orthogonal acceleration electrode is energized multiple times prior the release of a subsequent pulse or packet of ions.