FAIMS Sensor Apparatus with Dilution and Feedback Control
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Solution Overview
Problem
Ion mobility spectrometry systems, particularly FAIMS, face challenges in maintaining reliability and accuracy due to variations in ambient conditions, pump-induced pulsatility, and charge distribution issues, which complicate the detection of trace analytes and lead to contamination and sensitivity problems.
Innovation Solution
The system incorporates an IMS core with sensors for temperature, pressure, and humidity, a heated filter, scrubber, and recirculating flow path to control and stabilize conditions, adjust dilution ratios, and direct ions onto a detector electrode, while using bias electrodes to select ion polarity and operate in low power mode for efficient analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct sampling from ambient environment is used in highly sensitive FAIMS systems, then the system can detect down to parts-per-billion levels, but the system can be saturated by higher concentrations of analytes or interferents, thus hiding the analytes of actual interest
Solution Approach 1:
The patent introduces an intermediary dilution system between the ambient environment and the FAIMS sensor. This system includes a mixing chamber where ambient air is mixed with clean reference air, and a dilution controller that regulates the mixing ratio. The intermediary dilution system prevents high concentrations of analytes or interferents from directly entering the sensitive FAIMS detector, thereby avoiding saturation while still enabling detection at parts-per-billion levels.
2Measurement precision
If theoretical corrections are used for pressure and temperature effects, then corrections can be applied relatively simply, but not all environmental conditions can easily be corrected in this manner
Solution Approach 1:
The patent implements feedback control by continuously monitoring environmental conditions (temperature, pressure, humidity) using sensors and automatically adjusting system parameters to compensate for these variations. The system includes environmental sensors that feed data to a controller, which then adjusts the FAIMS operating parameters in real-time to maintain optimal performance across varying environmental conditions, eliminating the need for complex manual corrections.
3Productivity
If pumps are used to drive flow through the FAIMS system, then flow can be maintained, but pumps introduce pulsatility into the flow, which can distort FAIMS spectra
Solution Approach 1:
The patent extracts or removes the pump from the immediate FAIMS flow path. Instead of using a pump directly connected to the FAIMS instrument, the system employs passive flow control mechanisms such as pressure differentials, flow restrictors, or membrane-based flow regulation. This eliminates the pulsatility introduced by mechanical pumps while maintaining adequate flow rates through the FAIMS system, thereby preserving spectral quality.
4Adaptability or versatility
If multiple species are present in the FAIMS system, then the system can detect various analytes, but the finite amount of charge available is typically distributed between the species according to their concentrations and charge affinities, making it difficult to quantitatively judge the concentration
Solution Approach 1:
The patent segments the detection process by using multiple FAIMS detectors or multiple detection channels, each optimized for specific analyte groups. Alternatively, the system employs sequential analysis where different voltage conditions are applied to separate and detect different species in stages. This segmentation allows the finite charge to be allocated more effectively across multiple analytes, improving quantification accuracy while maintaining multi-analyte detection 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 configuration enhances sensitivity at low analyte concentrations, reduces contamination, stabilizes humidity, and improves accuracy by controlling environmental conditions and ion flow, allowing for precise detection and characterization of analytes under known conditions.
Implementation Method 1
Ionization techniques, in which a gas sample is ionized and then separated into constituent parts that can be detected individually
Implementation Method 2
a heated filter, scrubber, and recirculating flow path to control and stabilize conditions
Implementation Method 3
using bias electrodes to select ion polarity
Implementation Method 4
scrubber
Data Source
AI summary
An ion mobility gas detector apparatus including a detector core, an inlet gas path, an exhaust gas path, a source of diluent gas, and at least one or more sensors for measuring temperature, pressure and humidity of gas streams. Further included is a mixing mechanism adapted to mix at least first and second gas streams in response to one or more sensor measurements. A controller is provided for applying drive signals to the detector core.