Ambient Pressure Ionization Interface for DMS Analysis
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Solution Overview
Problem
Conventional methods for sample preparation in differential mobility spectrometry (DMS) are limited in analyzing non-volatile and semi-volatile substances, as they often result in fragmentation and are not suitable for high molecular weight compounds, and require operation under high vacuum, making them unsuitable for portable and field-deployable devices.
Innovation Solution
An interface assembly that utilizes ambient pressure matrix-assisted laser desorption ionization (AP-MALDI) and electrospray ionization (ESI) techniques to ionize and introduce samples into a DMS, allowing for the analysis of high molecular weight biological and non-biological molecules without fragmentation, and operates at ambient pressure, enabling portable and field-deployable systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sample preparation methods are used in DMS, then the system can operate under high vacuum, but it results in fragmentation of high molecular weight compounds and is not suitable for portable devices
Solution Approach 1:
The invention changes the operating pressure parameter from high vacuum to ambient pressure, enabling the use of AP-MALDI and ESI ionization techniques that preserve chemical integrity of high molecular weight compounds while eliminating the need for complex vacuum systems, making the device portable and field-deployable
Solution Approach 2:
The invention replaces the mechanical vacuum system with an ambient pressure operation mode, substituting the need for vacuum pumps and seals with ionization techniques (AP-MALDI and ESI) that function effectively at atmospheric pressure, thereby simplifying the device structure and enabling portability
2Manufacturing precision
If conventional ionization methods are used, then the system is simpler to operate, but it causes fragmentation and is not suitable for high molecular weight compounds
Solution Approach 1:
The invention changes the ionization method from conventional electron impact to AP-MALDI and ESI techniques, which use softer ionization mechanisms that deposit less energy on analyte molecules, thereby preventing fragmentation and improving resolution for high molecular weight compounds while maintaining operational simplicity through automated sample introduction
3Measurement precision
If the drift tube length is increased to improve resolution in TOF spectrometry, then better separation is achieved, but the device size increases and sensitivity decreases due to ion loss
Solution Approach 1:
The invention introduces a reflectron as an intermediary component in the flight path that reflects ions back toward the detector, effectively increasing the flight path length and resolution without proportionally increasing the physical device size, while minimizing ion loss through the use of electrostatic mirrors that efficiently reflect ions back into the detection region
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
Enables the analysis of high molecular weight molecules up to 100,000 Da, preserving chemical integrity and improving resolution, and facilitates the development of portable and field-deployable systems for detecting biological and chemical agents.
Implementation Method 1
an ionization source for producing ionized analyte from the sample, the ionization source including an ambient pressure matrix-assisted laser desorption ionization apparatus
Implementation Method 2
a laser for providing energy to desorb and ionize the analyte in the presence of the ionization-assisting matrix
Implementation Method 3
electrospray ionization (ESI) techniques to ionize and introduce samples into a DMS
Implementation Method 4
an ion flow generator that draws the ionized analyte from the ionization apparatus into the interface assembly and through the capillary tube
Implementation Method 5
a gas manifold assembly through which a carrier gas flows, the gas manifold assembly disposed in relation to the capillary tube to allow infusion of the ionized analyte into the carrier gas and delivery of the resulting gas stream into the ion mobility spectrometer
Data Source
AI summary
The invention provides an interface assembly for delivering an ionized analyte from an ionization apparatus into an ion mobility spectrometer. This allows analysis of biological and non-biological samples, even non-volatile solids, via differential mobility spectrometry, without fragmentation of molecules. The invention also provides portable sample analysis systems that operate at ambient pressure. Systems of the invention may be used for high molecular weight species detection, for example, drinking water contaminants, pathogenic biological agents, bio-organic substances, non-biological material, peptides, proteins, oligonucleotides, polymers, bacteria, and hydrocarbons.