Optochemical Sensor With Segmented Sensing Layers
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Solution Overview
Problem
Existing optochemical sensors face challenges in accurately measuring parameters like dissolved gases and temperature due to cross-sensitivity and slow response times, especially in applications where temperature changes are rapid, leading to potential measurement errors.
Innovation Solution
An optochemical sensor design featuring a substrate with physically separated sensing layers for temperature and analyte detection, where each layer is immobilized in a different polymer matrix, allowing for thinner layers and independent application techniques, reducing cross-sensitivity and enhancing response times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensing layers are combined in a single optochemical sensor to enable multi-parameter measurement, then measurement versatility is improved, but device complexity increases and response time deteriorates due to the additional layers
Solution Approach 1:
The sensor is divided into multiple independent sensing layers, each dedicated to measuring a specific parameter (e.g., dissolved oxygen, temperature, pH). This segmentation allows each layer to be optimized for its specific function with appropriate thickness and material composition, enabling fast response times while maintaining multi-parameter measurement capability.
Solution Approach 2:
Multiple sensing layers are arranged in a vertical stack configuration along the optical path between the light source and detector. This spatial arrangement in the third dimension (depth/thickness direction) allows simultaneous measurement of multiple parameters without increasing the lateral footprint, and each layer can be independently optimized for rapid response.
2Measurement precision
If temperature compensation is implemented using a separate temperature-sensitive layer, then measurement precision is improved, but cross-sensitivity between temperature and analyte detection increases
Solution Approach 1:
The temperature-sensitive layer and analyte-sensitive layer are designed with different local properties including distinct polymer matrices, different photoluminescence characteristics, and selective permeability. The analyte-sensitive layer uses a polymer matrix optimized for analyte diffusion while the temperature layer uses a matrix optimized for thermal response, reducing cross-sensitivity while enabling accurate temperature compensation.
Solution Approach 2:
A selective barrier layer or membrane is positioned between the measurement medium and the sensing layers to control which substances reach which sensors. This intermediary structure allows the temperature layer to sense temperature without being affected by dissolved gases, while the analyte layer can detect the analyte with minimal temperature interference.
3Duration of action of moving object
If sensing layers are made thinner to improve response time, then response time is improved, but manufacturing precision requirements increase due to difficulty in applying and controlling thin layer uniformity
Solution Approach 1:
The sensing layers are designed with optimized thickness parameters in the range of 1-10 micrometers, which is thin enough for rapid analyte diffusion and fast response times, but thick enough to maintain adequate photoluminescence signal intensity. This parameter optimization balances response speed with manufacturing feasibility and signal detection capabilities.
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 design enables simultaneous, accurate measurement of multiple parameters with improved response times and reduced temperature cross-sensitivity, enhancing the sensor's stability and precision in dynamic environments.
Implementation Method 1
In optochemical sensors based on photoluminescence, a reduction of photoluminescence caused by the analyte is detected, known as photoluminescence quenching. Under this principle, the molecules of an indicator are excited by irradiation with light of a suitable wavelength. As the molecules relax from the excited state back to the ground state, they release the absorbed energy again in the form of photoluminescence. Physical interaction between the analyte and the indicator causes enhanced relaxation via a non-radiative channel, which leads to decrease of the photoluminescence intensity and increase of the relaxation rate-quenching.
Implementation Method 2
Baleizao et al. (Anal. Chem. 80, 6449-6457, 2008) describe a dual fluorescence sensor that takes into account the effect of temperature on the oxygen sensor. Two sensor layers containing two luminescent compounds for oxygen and temperature respectively were prepared over a polyester support.
Data Source
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AI summary
An optochemical sensor (202) based on an optical-sensing technique for determining more than one parameter in a measurement medium (204) comprising an optochemical sensitive element (208) comprising a first sensing layer (228), a second sensing layer (230), wherein the first sensing layer and the second sensing layer are arranged on a substrate (222). The first sensing layer comprises a first indicator (236) to determine a first parameter whereas the second sensing layer comprises a second indicator (238) to determine a second parameter in the measurement medium.