Microfluidic ESI-MS Interface With Feedback Voltage Control
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Solution Overview
Problem
Current methods for interfacing protein sample preparation techniques with mass spectrometers, such as liquid chromatography and electrospray ionization, are limited by the need for peptide fragment analysis and lack of tools for maintaining constant voltage at the electrospray ionization tip, leading to suboptimal sample processing and data quality.
Innovation Solution
The method involves maintaining a constant voltage at the electrospray ionization tip by applying voltages to a separation channel and an auxiliary fluid channel, using a feedback loop to adjust for changes in resistance and voltage, and imaging the analyte peaks to determine their velocity and timing for correlation with mass spectrometer data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid chromatography is used to prepare protein samples for mass spectrometry, then sample fractions can be collected for analysis, but the proteins must be digested into peptide fragments which increases the number of fractions and data complexity
Solution Approach 1:
The patent extracts the voltage control function from the mass spectrometer and implements it independently at the electrospray ionization tip through a feedback control system. This separation allows the tip voltage to be maintained constant regardless of changes in fluid resistance or flow conditions, thereby simplifying the overall system operation and improving interface reliability between the microfluidic device and mass spectrometer.
Solution Approach 2:
The patent implements a feedback control system that continuously monitors the voltage at the electrospray ionization tip and adjusts the applied voltage to maintain a constant tip voltage. This feedback mechanism compensates for changes in fluid resistance and flow conditions, ensuring stable electrospray performance and improving the reliability of sample introduction to the mass spectrometer.
2Adaptability or versatility
If electrospray ionization is used to introduce samples into the mass spectrometer, then intact proteins can be analyzed, but the voltage at the ESI tip must remain constant which is challenging when internal fluid resistances change
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the voltage at the electrospray ionization tip and adjusts the applied voltage to maintain a constant tip voltage. This feedback mechanism compensates for changes in fluid resistance and flow conditions, ensuring stable electrospray performance and improving the reliability of sample introduction to the mass spectrometer.
Solution Approach 2:
The patent transitions from a static voltage application system to a dynamic feedback control system that continuously adjusts the voltage based on real-time conditions. This dynamic approach allows the system to adapt to changing fluid resistance and flow conditions while maintaining constant tip voltage, thereby improving both reliability and adaptability.
3Ease of operation
If capillaries are used for electrospray ionization, then a convenient droplet volume can be provided, but the linear flow path does not allow for multi-step sample processing
Solution Approach 1:
The patent segments the sample processing function from the electrospray ionization function by using a microfluidic device with multiple channels for sample preparation and a separate capillary for ESI. This segmentation allows multi-step sample processing in the microfluidic device while maintaining the advantages of capillary-based electrospray ionization, thereby improving both versatility and ease of operation.
Solution Approach 2:
The patent nests the capillary electrospray interface within a larger microfluidic device that performs multi-step sample processing. The capillary is integrated into the microfluidic channel network, allowing the compact ESI function to be embedded within the more complex sample preparation system, thereby achieving both multi-step processing capability and convenient droplet volume control.
4Ease of operation
If microfluidic devices are used for sample preparation, then additional control and complexity for fluid manipulations can be provided, but limited characterization of separated analyte fractions is available prior to mass spectrometry introduction
Solution Approach 1:
The patent merges the microfluidic sample preparation device with the electrospray ionization interface and mass spectrometry detection system into an integrated platform. This integration allows the full benefits of microfluidic control to be realized while simultaneously capturing comprehensive characterization data through coupled online detection methods, thereby preventing information loss and improving overall analytical capability.
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 approach allows for improved characterization of analyte peaks and enhanced correlation between chemical separation and mass spectrometry data, enabling more accurate analysis of complex mixtures, including biologic drugs, by maintaining stable electrospray performance and precise control over sample processing.
Implementation Method 1
electrospray ionization (ESI). In ESI, small droplets of sample and solution are emitted from a distal end of a capillary or microfluidic device comprising an electrospray feature, such as an emitter tip or orifice, by the application of an electric field between the capillary tip or emitter tip and the mass spectrometer source plate. The droplet stretches and expands in this induced electric field to form a cone shaped emission (i.e., a 'Taylor cone') which comprises increasingly small droplets that evaporate and produce the gas phase ions that are introduced into the mass spectrometer
Implementation Method 2
Separation of analyte components from a more complex analyte mixture on the basis of an inherent quality of the analytes
Data Source
AI summary
Methods, devices, and systems for improving the quality of electrospray ionization mass spectrometer (ESI-MS) data are described, as are methods, devices, and systems for achieving improved correlation between chemical separation data and mass spectrometry data.