Multi-nozzle Electrospray Chip with Sheath Gas Envelope
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Solution Overview
Problem
Existing multi-nozzle electrospray systems for mass spectrometry face challenges in achieving uniform spraying and minimizing ion losses, particularly in transferring analyte ions from a chromatograph to a mass spectrometer's vacuum system with high efficiency.
Innovation Solution
A multi-nozzle chip design where each spray nozzle is surrounded by sheath gas nozzles and a shared attracting-voltage electrode with a tapering opening, ensuring uniform spraying and optimal ion transfer into the vacuum system through a multichannel inlet plate, with self-regulating liquid supply and heating of sheath gas to enhance drying and ion mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple spray nozzles are arranged in parallel to increase ion yield, then the total ion yield increases as √n, but the uniformity of spraying across all nozzles deteriorates and ion losses increase
Solution Approach 1:
The patent divides the common liquid supply into separate individual supply lines for each spray nozzle, allowing independent control and optimization of spray parameters for each nozzle. This segmentation enables uniform spraying across all nozzles while maintaining high ion yield, resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent implements local quality control by providing individual sheath gas supply to each spray nozzle and individual attracting voltage electrodes for each nozzle. This allows optimization of local conditions (gas flow, voltage) for each nozzle to ensure uniform spraying performance across the array, preventing the deterioration of spray uniformity that would occur with parallel operation.
2Productivity
If sheath gas flow is used to envelope the spray jet, then ion transfer efficiency into vacuum improves, but the complexity of the device increases due to additional gas supply systems
Solution Approach 1:
The patent merges the sheath gas supply function with the existing liquid supply manifold by integrating gas channels into the same structural platform. The sheath gas nozzles are positioned around each spray nozzle in a coordinated arrangement, allowing the gas supply system to be implemented without adding significant structural complexity while achieving high ion transfer efficiency into the vacuum system.
3Productivity
If nanospraying is used to achieve high analyte ion yield, then the ion yield approaches 100%, but the liquid flow rate is limited to 10-100 nanoliters per minute
Solution Approach 1:
The patent transitions from single-nozzle nanospraying to a multi-nozzle array configuration, adding the spatial dimension of multiple parallel nozzles. This allows the system to maintain the high efficiency of nanospraying (100% analyte ion yield) while increasing the total liquid flow rate capacity by operating multiple nozzles simultaneously, each handling small flow rates but collectively processing much larger volumes.
4Force
If a shared counterelectrode with individual openings is used, then the attracting field is established, but ion losses occur on the electrode surfaces and no sheath gas guidance is provided
Solution Approach 1:
The patent introduces sheath gas as an intermediary medium between the spray jet and the counterelectrode surface. The sheath gas flows along the spray jet path, creating a protective envelope that prevents ions from contacting and discharging on the electrode surfaces. This intermediary gas flow maintains the attracting field strength while eliminating ion losses on the electrode surfaces.
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 design significantly increases the yield of analyte ions by preventing ion discharge and ensuring uniform spraying, allowing for efficient transfer of ions into the mass spectrometer with reduced losses, potentially achieving an n-fold increase in ion yield and concurrent substance peak delivery.
Implementation Method 1
each spray nozzle being surrounded by sheath gas nozzles, preferably in a symmetric arrangement, for the jet-like feeding in of a sheath gas
Implementation Method 2
The chip contains a shared attracting-voltage electrode which extends over all the spray nozzles
Implementation Method 3
The attracting-voltage electrode may have a tapering (e.g. funnel-shaped) opening above each spray nozzle so that the jets of sheath gas are directed toward the spray jet in this opening
Implementation Method 4
heating of sheath gas to enhance drying and ion mobility
Data Source
AI summary
The invention involves electrospray ionization of dissolved substances at atmospheric pressure in the ion source of a mass spectrometer. A chip with a multitude of spray nozzles is proposed, where each individual spray nozzle is surrounded by several sheath gas nozzles, preferably in a symmetric arrangement, for the jet-like introduction of a sheath gas. A shared attracting-voltage electrode is positioned substantially opposite the spray nozzles. The attracting-voltage electrode may have a tapering (e.g. funnel-shaped) opening above each spray nozzle so that the sheath gas jets are forced to closely envelop the spray jet, which is comprised of ions and very fine droplets. Heavier ions and droplets are thus prevented from discharging on the surfaces of the openings of the attracting-voltage electrode. Special measures can be taken to make all spray nozzles spray uniformly and to supply them with substance peaks from chromatographic or electrophoretic separators as simultaneously as possible.