RF Plasma Ion Source for Ambient Spectrometry

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Solution Overview

Problem

Existing ambient ionization techniques for mass spectrometry, such as DART, ESI, and MALDI, face challenges including high gas consumption, complex spectra interpretation, requirement for sample preparation, use of solvents, and limitations in analyzing low molecular weight compounds, making them inefficient and costly for certain applications.

Innovation Solution

A plasma-based ion source that utilizes a plasma generator capable of switching between desorption and ionization modes using radio frequency energy, allowing independent control over these processes without additional heating components, and capable of generating plasma from various gas species, enabling efficient analyte desorption and ionization with minimal sample preparation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If DART technique is used for ambient ionization, then ionization of analytes is achieved, but gas consumption is high and spectra interpretation becomes complex

Engineering Contradiction:
Improveionization efficiencyVSAvoidgas consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent segments the plasma generation process into distinct operational modes (ionization mode and desorption mode) that can be independently controlled. This allows the system to achieve ionization efficiency when needed while reducing gas consumption during desorption operations, resolving the contradiction between reliable ionization and excessive gas usage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different plasma generation modes based on operational requirements. By making the plasma generation process adjustable and controllable in real-time, the system can optimize gas consumption while maintaining ionization efficiency, directly addressing the contradiction between these two parameters.

Inventive Principle:
Principle #15Dynamics

2Reliability

If DART technique is used for ambient ionization, then ionization of analytes is achieved, but spectra interpretation becomes complex

Engineering Contradiction:
Improveionization efficiencyVSAvoidspectra interpretation complexity
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent separates desorption and ionization into distinct operational modes, allowing independent optimization of each process. This segmentation enables cleaner spectra by controlling when and how ionization occurs, reducing the complex chemical interactions that make spectra interpretation difficult while maintaining ionization efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes operational parameters (plasma generation conditions, gas flow rates, power levels) to optimize the ionization process. By carefully controlling these parameters, the system achieves reliable ionization while minimizing unwanted chemical reactions and background interference that complicate spectra interpretation.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If additional heating components are added to control desorption, then desorption control is improved, but device complexity increases

Engineering Contradiction:
Improvedesorption controlVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent makes the plasma generating component multi-functional by enabling it to perform both ionization and desorption functions. This eliminates the need for separate heating components, as the plasma component itself can control desorption through parameter adjustment, thereby improving ease of operation without increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system merges the desorption control function into the plasma generating component. By combining multiple functions (ionization, desorption, heating) into a single component, the system achieves improved desorption control while avoiding the addition of separate heating components, thus resolving the contradiction between operational ease and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If MALDI technique is used for ionization, then ionization of analytes is achieved, but sample preparation requirements and cost of laser hardware increase

Engineering Contradiction:
Improveionization efficiencyVSAvoidsample preparation and equipment cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive, complex equipment (laser systems, matrix materials) with a more economical plasma generation system. The plasma component can be implemented using relatively simple and cost-effective methods, eliminating the need for costly laser hardware and complex sample preparation procedures while maintaining reliable ionization efficiency.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The system substitutes the mechanical and optical complexity of laser-based MALDI systems with an electromagnetic plasma generation approach. This replacement eliminates the need for expensive laser hardware and complex sample matrix preparation, achieving reliable ionization through a simpler, more cost-effective mechanism.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution provides cost-effective, flexible, and controlled analyte desorption and ionization, enabling the analysis of small molecules without complex sample preparation, reducing gas consumption, and interfacing with multiple spectrometric techniques like MS, IMS, and OES.

Implementation Method 1

in the desorption mode, the plasma generating component applies radio frequency energy effective for heating the sample without generating plasma

Methodology Applied
Scientific EffectRadio frequency heating: Dielectric Heating

Implementation Method 2

in the ionization mode, the plasma generating component applies radio frequency energy effective for generating plasma from the plasma precursor gas

Methodology Applied
Scientific EffectPlasma generation: Plasma

Implementation Method 3

Once analyte ions are formed they are transferred into the MS

Methodology Applied
Scientific EffectIonization: Ionisation

Data Source

PatentEP3062331B1Ambient desorption, ionization, and excitation for spectrometry
Publication Date: 2020.12.23 AGILENT TECHNOLOGIES INC
  • EP3062331B1 patent drawingFigure 1
  • EP3062331B1 patent drawingFigure 2A~3
  • EP3062331B1 patent drawingFigure 4

AI summary

An ion source (100; 400; 700; 1400) includes a plasma generator (104; 404; 1404) for supplying plasma at an ionization region proximate to a sample surface (120; 1120; 1220; 1320; 1420). The plasma generator applies energy that may be utilized for desorbing analytes from the sample surface as well as for generating plasma by which analytes are excited or ionized. Desorption and ionization/excitation may be controlled as individual modes. The ion source may be interfaced with an analytical instrument (118) such as an ion-based or optical-based spectrometer. A sample support (108; 708) may be provided, which may be capable of performing analytical separation.