Microfluidic Reference Sensor for Liquid Component Sensing
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Solution Overview
Problem
Existing methods for detecting and quantifying components in liquids face challenges in accurately compensating for background and environmental effects, such as drifts and temperature variations, which can lead to inaccurate measurements.
Innovation Solution
A sensing system utilizing a half-closed microfluidic channel where the reference sensor is positioned far from the open end, allowing only slow variations of solute concentration to reach it, thereby averaging out fast changes and providing a more accurate reference signal for filtering out background influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a blank measurement is used to generate a reference signal, then the reference signal can be obtained in advance, but it cannot accurately compensate for real-time background and environmental effects
Solution Approach 1:
The reference sensor continuously measures the liquid sample to generate an updated reference signal, rather than using a pre-recorded blank measurement. This continuous measurement ensures the reference signal reflects real-time background and environmental effects, improving compensation accuracy while maintaining efficient operation.
Solution Approach 2:
The system uses the reference sensor output as feedback to continuously update the reference signal. This feedback mechanism allows the system to adapt to changing background conditions and environmental effects in real-time, resolving the contradiction between using advance measurements and achieving accurate real-time compensation.
2Measurement precision
If a dual-beam reference arm is created to cancel common variations, then the signal-to-noise ratio is enhanced, but it is difficult to provide a proper reference sample
Solution Approach 1:
The reference sensor serves multiple functions: it measures the liquid sample to generate the reference signal, it detects background effects, and it provides continuous monitoring. By making the reference sensor universal in its function, the system eliminates the need for separate reference samples while maintaining the dual-beam noise cancellation capability.
Solution Approach 2:
The reference sensor acts as an intermediary that measures the liquid sample itself rather than requiring a separate reference sample. This intermediary approach allows the system to use the actual sample as the reference medium, simplifying the system while maintaining enhanced signal-to-noise ratio through common variation cancellation.
3Measurement precision
If the reference sensor is placed far from the open end of the microfluidic channel, then fast variations of solute concentration are averaged out, but the reference sensor is less responsive to real-time changes
Solution Approach 1:
The reference sensor is positioned to receive solute concentration variations after they have been partially averaged by diffusion through the microfluidic channel. This preliminary averaging action filters out high-frequency noise while the continuous measurement capability maintains responsiveness to real-time trends, resolving the contradiction between accuracy and speed.
Solution Approach 2:
The system changes the spatial parameter (position of reference sensor) to optimize the balance between averaging fast variations and maintaining responsiveness. By carefully selecting the position along the microfluidic channel, the system achieves optimal filtering of noise while preserving sensitivity to meaningful concentration changes.
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 enables continuous, accurate detection and quantification of components by using a reference signal that accounts for real-time background and environmental effects, improving the precision of measurements and allowing for compact, single-channel configurations suitable for various sensor types.
Implementation Method 1
the reference sensor typically is placed far from the open end of the half closed microfluidic channel and the solute can only reach the reference sensor through the process of diffusion in a confined region
Data Source
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AI summary
A sensing system and method for sensing a component in a liquid is disclosed. The system comprises a microfluidic channel, the microfluidic channel comprising a first end and a second end, wherein the microfluidic channel is open at the first end and closed at the second end. The system also comprises at least one measurement sensor positioned adjacent the first end, the measurement sensor being arranged for detecting a measurement signal and a reference sensor positioned in the microfluidic channel adjacent the second end, the reference sensor being arranged for detecting a reference signal of the liquid. The system further is configured for combining the measurement signal and the reference signal so as to filter out background influences.