Micro-Electrospray Emitter Geometry for High-Flow Sensitivity
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Solution Overview
Problem
Current electrospray ionization (ESI) methods struggle to achieve high sensitivity and ionization efficiency at flow rates above 1 μL/min, while maintaining the ruggedness and ease of operation associated with higher flow rates.
Innovation Solution
The development of a novel ESI emitter device with a uniquely shaped and constructed nozzle, featuring a microbend and a frit within its outlet, which directs electrostatically charged droplets towards the highest velocity region of the sheath gas flow, enabling operation at flow rates from 1 μL/min to 100 μL/min.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ESI emitters are used, then operation at higher flow rates (above 1 μL/min) is possible, but sensitivity and ionization efficiency deteriorate
Solution Approach 1:
The emitter incorporates an asymmetric beveled outlet geometry where the outlet is angled relative to the emitter axis, creating an asymmetric spray pattern that directs the Taylor cone jet toward the high-velocity region of the sheath gas flow. This asymmetric configuration optimizes droplet formation and ionization efficiency at higher flow rates, resolving the contradiction between productivity and measurement precision.
Solution Approach 2:
The emitter design features a localized beveled section at the outlet with specific angular geometry, concentrating the ionization effect in the region where sheath gas velocity is highest. This local geometric modification improves ionization efficiency specifically at the outlet zone without affecting the overall flow rate capability of the emitter.
2Measurement precision
If nanospray is used, then sensitivity is improved, but operation is limited to flow rates of 1 μL/min or less
Solution Approach 1:
The asymmetric beveled outlet geometry redirects the Taylor cone jet to align with the sheath gas flow direction, creating an optimized spray pattern that maintains nanospray-level sensitivity while accommodating higher flow rates. The asymmetric design allows the emitter to leverage sheath gas assistance effectively, breaking the flow rate limitation of conventional nanospray.
3Stability of the object's composition
If beveled nozzles are used, then stability at lower flow rates is improved, but optimal flow rate cannot exceed 1 μL/min
Solution Approach 1:
The asymmetric bevel angle and outlet orientation create a spray pattern that is optimized for higher flow rates by directing the ionization region into the high-velocity sheath gas zone. This asymmetric configuration expands the optimal operating range to above 1 μL/min while preserving signal stability through consistent droplet formation in the optimized flow field.
Solution Approach 2:
The emitter design changes the geometric parameters of the outlet (bevel angle, outlet orientation relative to axis) to optimize performance at higher flow rates. By adjusting these geometric parameters, the emitter maintains stable Taylor cone formation and consistent spray characteristics across an expanded flow rate range.
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 allows for high sensitivity analysis comparable to nanospray at higher flow rates, balancing sensitivity and ruggedness, and is compatible with microflow LC columns, enhancing the performance of ESI-MS systems.
Implementation Method 1
The electrically charged liquid is broken up into a plume of small droplets by the flow of high velocity sheath gas
Implementation Method 2
Solvent evaporation in the charged droplets then takes place and the electrically charged sample is ionized
Implementation Method 3
directs electrostatically charged droplets towards the highest velocity region of the sheath gas flow
Data Source
AI summary
Disclosed is an emitter device configured to operate as part of an electrospray ionization mass spectrometry device, the emitter device providing droplets of a liquid containing material to be analyzed. Also disclosed are methods of use of the emitter device 1.