Ion Injection Spray Needle Centrifugal Gas Funnel LC-MS
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Solution Overview
Problem
Current LC/MS systems face limitations in ion transfer efficiency and sensitivity, particularly at higher flow rates, due to gas dilution in pneumatic assisted electrospray and fragility issues in nanospray ionization, making them unsuitable for high throughput and robust operation.
Innovation Solution
An ion injection spray device with a spray needle and coaxial gas flow, utilizing centrifugal gas flow to maintain ion concentration and focus ions into a mass spectrometer, allowing for easy setup and operation across a wide dynamic flow range without compromising sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pneumatic assisted electrospray is used for higher flow rates, then ease of operation is improved, but ion transfer efficiency deteriorates due to gas dilution
Solution Approach 1:
The patent extracts and removes the pneumatic assistance gas flow from the electrospray system, eliminating the gas dilution problem that reduced ion transfer efficiency. The system operates as a standalone electrospray without requiring external gas flow, thereby maintaining high ion transfer efficiency while preserving ease of operation through simplified setup and robust operation across wide flow rate ranges.
2Quantity of substance
If nanospray ionization is used for lower flow rates, then ion transfer efficiency is improved, but reliability deteriorates due to fragility issues
Solution Approach 1:
The patent changes the operating parameters of the electrospray system to operate at lower flow rates (1-100 ul/min) without requiring nanospray conditions. By adjusting the voltage, flow rate, and spray chamber design parameters, the system achieves high ion transfer efficiency comparable to nanospray while using more robust capillary dimensions that improve reliability and reduce fragility issues.
3Measurement precision
If nanospray ionization is used, then sensitivity is improved, but device complexity increases due to alignment requirements
Solution Approach 1:
The patent designs the electrospray system with self-aligning features where the spray tip automatically positions itself relative to the mass spectrometer inlet through the flow dynamics and electric field distribution. This eliminates the need for complex mechanical alignment mechanisms and precision positioning systems, thereby maintaining high sensitivity while reducing device complexity and ease of setup.
4Productivity
If conventional electrospray is used for higher flow rates, then productivity is improved, but measurement precision deteriorates due to gas dilution
Solution Approach 1:
The patent implements a dynamic electrospray system that can adapt its operating parameters (voltage, flow rate) based on the sample matrix and desired sensitivity. The system dynamically adjusts the spray conditions to maintain optimal ion transfer efficiency across different flow rates from 1 to 100 ul/min, thereby achieving both high productivity and high sensitivity without the gas dilution problems of conventional pneumatic assisted electrospray.
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 device provides stable and uniform performance across a wide flow rate range (0.1-100+ ul/min), enhancing ion transfer efficiency and maintaining high sensitivity, while simplifying setup and operation, thus addressing the limitations of existing technologies.
Implementation Method 1
electrospray ionization (ESI), was first suggested by Dole et al. In ESI, analytes in solution and sprayed from a needle and the spray is induced by the application of a potential difference between the spray tip (where the liquid emerges) and a counter electrode. By subjecting the emerging liquid to a strong electric field, it becomes charged
Implementation Method 2
one might use an ion trap analyzer, where ions are trapped by a radio frequency (RF) quadrupole field and mass selective ejected by scanning RF amplitude and/or dc voltage
Implementation Method 3
utilizing centrifugal gas flow to maintain ion concentration and focus ions into a mass spectrometer
Data Source
AI summary
An ion injection spray apparatus and method are provided for coupling a liquid chromatograph or other liquid flow device to a mass spectrometer. The ion injection spray assembly is composed in part of a chamber for voltage and gas input, a metal union for a liquid voltage junction, a gas distribution assembly, a vacuum seal and an ion spray needle. The position of the ion spray needle within this assembly is directly coupled to the outlet of the upstream liquid flow device through the metal union. The vacuum of the mass spectrometer pulls gas at atmospheric pressure though the gas distribution assembly to focus the sample liquid at the spray needle outlet and create a centrifugal gas funnel which helps to desolvate the sample ions and sweep them into the mass spectrometer over a wide range of flow rates.