Separate Desolvation and Carrier Gas Inlets for FAIMS
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Solution Overview
Problem
High Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) is sensitive to moisture and contaminants, leading to signal loss and apparatus failure when using mixed gases for desolvation and ion transport, resulting in high consumption of expensive carrier gases.
Innovation Solution
A FAIMS apparatus with separate desolvation and carrier gas inlets, where a desolvation gas is used to counter-currently desolvate ions in a desolvation chamber and a distinct carrier gas, such as helium, is introduced separately into the analytical gap for ion transport, reducing the need for expensive gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a mixed gas flow is used for both desolvation and ion transport in FAIMS, then ion desolvation is achieved, but expensive carrier gas consumption increases and FAIMS sensitivity to contaminants is worsened
Solution Approach 1:
The gas flow system is segmented into two separate pathways: a desolvation gas flow that enters the ESI chamber to remove solvent molecules from ions, and a carrier gas flow that enters the FAIMS analyzer to transport ions. This segmentation allows each gas to be optimized for its specific function, reducing carrier gas consumption while maintaining FAIMS performance
Solution Approach 2:
The desolvation function is extracted from the carrier gas system and performed by a separate desolvation gas in the ESI chamber. This extraction prevents solvent contaminants from being introduced into the FAIMS analyzer with the carrier gas, thereby protecting FAIMS sensitivity while reducing expensive carrier gas usage
2Quantity of substance
If electrospray ionization is used to produce ions, then ion generation is achieved, but high levels of water and volatile solvents are introduced into the FAIMS system
Solution Approach 1:
A desolvation gas acts as an intermediary between the ESI ion source and the FAIMS analyzer. This intermediary gas flows counter-current to the ion plume, facilitating solvent evaporation and removal before ions enter the FAIMS system, thereby protecting against moisture and solvent contamination
Solution Approach 2:
Desolvation is performed as a preliminary action before ions enter the FAIMS analyzer. The desolvation gas removes solvent molecules from the ion plume in the ESI chamber, preventing contaminants from reaching the FAIMS system where they would cause signal loss or malfunction
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 configuration reduces the consumption of expensive carrier gases like helium by using less expensive gases, such as nitrogen, for desolvation while maintaining effective ion separation and transport in the FAIMS apparatus.
Implementation Method 1
a first portion of the gas flow, which is referred to as the counter-current of gas, enters the ESI chamber so as to desolvate the ions
Implementation Method 2
the remainder of the gas flow enters the FAIMS via the ion inlet orifice and serves as the carrier gas for transporting ions within the FAIMS analyzer
Implementation Method 3
The field-dependent change in the mobility of the ions causes the ions to drift toward the walls of the analytical gap. Since the dependence of ion mobility on electric field strength is compound specific, this leads to a separation of the different types of ions
Data Source
AI summary
A method for analyzing ions includes providing a desolvation chamber in communication with an analytical gap of a FAIMS analyzer, via an ion inlet orifice. A flow of ions is introduced into the desolvation chamber along a flow path that is toward the ion inlet orifice and into the analytical gap of the FAIMS analyzer. A flow of a desolvation gas is provided into the desolvation chamber via a first gas inlet, such that a portion of the flow of the desolvation gas is counter-current to the flow of ions. A flow of a carrier gas is provided separately via a second gas inlet, which is defined downstream relative to the desolvation chamber. In particular, the composition of the carrier gas is different than the composition of the desolvation gas. Accordingly, the flow of the carrier gas is provided substantially into the analytical gap for transporting ions along a path between the ion inlet orifice and an ion outlet orifice of the analytical gap.