Shaped Electrospray Emitter Aperture for Stable Multi-Droplet Ionization

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Solution Overview

Problem

Existing electrospray ionization (ESI) mass spectrometry methods face limitations in ionization efficiency due to space charge repulsion between adjacent plumes, and there is a need for improved droplet stream mixing with nebulizing gas flow to enhance sensitivity.

Innovation Solution

A single nozzle emitter geometry with a shaped aperture is used to produce multiple droplet streams with defined nucleation points, incorporating a sheath gas flow to enhance droplet stream mixing and desolvation, thereby stabilizing and reproducibly directing the droplets towards the mass spectrometer inlet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple nozzles are used to increase ion current, then sensitivity is improved, but space charge repulsion between adjacent plumes reduces ionization efficiency

Engineering Contradiction:

Improveion currentVSAvoidspace charge repulsion

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The single nozzle aperture is segmented into multiple emission sites along its perimeter, creating multiple Taylor cones and droplet streams from one physical nozzle. This segmentation allows multiple plumes to be generated without the space charge repulsion issues that would arise from using multiple separate nozzles, as the plumes originate from a unified flow source with controlled spacing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the nozzle aperture are utilized to create emission sites at specific locations, with the radius of curvature varied locally to control Taylor cone formation. This local quality approach ensures optimal ionization at each emission site while maintaining overall system stability through the unified nozzle structure.

Inventive Principle:

Principle #3Local quality

2Productivity

If multiple nozzles are used to improve sensitivity, then droplet stream mixing with nebulizing gas is enhanced, but device complexity increases

Engineering Contradiction:

ImprovesensitivityVSAvoidnumber of nozzles

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Multiple emission sites and droplet streams are merged into a single nozzle structure, combining the functions of what would traditionally require multiple separate nozzles. This merging achieves the desired droplet stream mixing with nebulizing gas for enhanced sensitivity while maintaining the simplicity of a single nozzle device, avoiding the complexity of multiple independent nozzle assemblies.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If a single nozzle is used to simplify device structure, then device complexity is reduced, but ionization efficiency is limited by lack of droplet stream mixing

Engineering Contradiction:

Improvenozzle structureVSAvoidinsufficient droplet stream mixing

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of increasing the number of nozzles in one dimension, the invention utilizes the perimeter of the single nozzle aperture to distribute multiple emission sites in a spatial arrangement that promotes droplet stream mixing with the nebulizing gas flow, enhancing ionization efficiency while maintaining structural simplicity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 solution increases ionization efficiency by promoting droplet stream mixing and desolvation, leading to improved sensitivity and stability in electrospray ionization processes.

Implementation Method 1

approaches that promote mixing between droplet streams and a surrounding nebulizing gas flow

Methodology Applied

Scientific EffectMixing:

Implementation Method 2

enhance droplet stream mixing and desolvation

Methodology Applied

Scientific EffectDesolvation:

Implementation Method 3

electrospray ionization (ESI) mass spectrometry

Methodology Applied

Scientific EffectElectrospray ionization: Electrohydrodynamics

Implementation Method 4

establishing an electric field at the distal end of the flow channel to produce a plurality of droplet streams

Methodology Applied

Scientific EffectElectric field: Electric Field

Implementation Method 5

produce a reproducible multi-droplet spray with defined nucleation points

Methodology Applied

Scientific EffectNucleation: Nucleation

Implementation Method 6

initial droplet sizes emanating from a Taylor cone

Methodology Applied

Scientific EffectTaylor cone:

Data Source

PatentUS20250336661A1Electrospray emitter with non-uniform radius of curvature

Publication Date: 2025.10.30 THERMO FINNIGAN LLC

AI summary

Multiple droplet streams are produced with shaped apertures that are situated at distal ends of flow members. The droplet streams interact with and are desolvated by a shear gas flow. A variable number of droplet streams at fixed locations can be produced by selection of a suitable extraction electric field.