IMS Sample Introduction via Direct ESI Needle Coupling
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Solution Overview
Problem
In ion mobility spectrometry, sample dilution and loss occur due to injector valve, connector, and transfer line dead volumes, leading to compromised detection limits and increased solvent consumption, especially when handling small sample amounts.
Innovation Solution
Configuring the ion detector at the highest potential of the drift tube and the ionization source at ground or near ground potential, using a single syringe for direct sample introduction via electrospray ionization, and eliminating the need for injector valves and transfer lines by integrating the sampling and spray needle as a reusable or disposable auto-injector, which delivers samples directly into the ion mobility drift tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a longer dielectric liquid transfer line is used to allow gradual potential drop, then sample heating and electrophoretic effects are minimized, but liquid dead volume increases causing sample dilution and loss
Solution Approach 1:
The patent removes the transfer line from the system entirely by directly coupling the injector valve outlet to the ESI needle inlet, eliminating the source of dead volume while maintaining the necessary potential gradient through direct connection
Solution Approach 2:
The injector valve outlet and ESI needle inlet are merged into a direct connection, eliminating the intermediate transfer line and its associated dead volume, thus reducing sample dilution and loss
2Ease of operation
If injector valves and transfer lines are used for sample delivery, then sample introduction is achieved, but liquid dead volume causes sample dilution and compromises detection limits
Solution Approach 1:
The patent extracts and removes the transfer line component from the sample delivery system, directly connecting the injector valve to the ESI needle, thereby eliminating dead volume that compromises detection sensitivity
Solution Approach 2:
The system is segmented into discrete functional zones with direct coupling between injector and ESI source, eliminating intermediate components that contribute to dead volume and sample loss
3Ease of operation
If multiple components (injector valve, transfer lines, connectors) are used in sample delivery, then sample introduction functionality is achieved, but device complexity and apparatus costs increase
Solution Approach 1:
The patent merges the injector valve outlet directly with the ESI needle inlet, eliminating intermediate transfer lines and connectors, thus reducing device complexity and apparatus costs while maintaining sample delivery functionality
Solution Approach 2:
The direct coupling design serves multiple functions simultaneously: sample delivery, potential gradient establishment, and dead volume elimination, reducing the need for separate specialized components
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 reduces cross-contamination, solvent consumption, and liquid dead volume, enhancing sample throughput and analytical sensitivity while minimizing apparatus costs and solvent waste.
Implementation Method 1
a single syringe for sample introduction via an electrospray ionization method
Implementation Method 2
Ion mobility spectrometer (IMS) applications
Data Source
AI summary
The IMS apparatus and methods described in this invention involve setting the ion detector at the highest potential of the drift tube and setting the ionization source at ground or near ground potential. The methods allow significantly simple sample introduction without the limitation of the high potential (voltage) concern of the front end sample delivery. The invention also describes bringing samples directly into the ion mobility drift tube. The invention further describes using single syringe for sample introduction via an electrospray ionization method.