Ammonia Breath Sensor Using Humidity-Conditioned Optical Detection
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Solution Overview
Problem
Current methods for sensing ammonia in breath face challenges due to low concentrations and the presence of water, which complicates separation and detection, especially in field or home settings, as existing technologies are either large, expensive, or lack sensitivity and specificity.
Innovation Solution
A method and apparatus that condition the breath sample to optimize relative humidity, allowing interaction with an ammonia-reactive indicator that changes optically in response to ammonia levels, enabling accurate and reliable detection down to 0.2 ppm concentrations using a portable, cost-effective device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ammonia sensing methods are used, then detection capability is achieved, but device size and cost increase significantly
Solution Approach 1:
The patent extracts the essential sensing function from complex conventional systems by using a simple optical sensor combined with a chemically-modified indicator layer. The indicator layer contains ammonia-reactive groups that produce optical signals, eliminating the need for large, expensive conventional sensors while maintaining detection capability.
Solution Approach 2:
The patent employs a disposable sensor cartridge containing the optical sensor and indicator layer. This single-use component is inexpensive to manufacture and can be discarded after use, avoiding the need for expensive, maintainable conventional sensing systems while providing reliable ammonia detection.
2Ease of operation
If breath sample analysis is performed directly, then measurement is simplified, but water interference reduces detection accuracy
Solution Approach 1:
The patent introduces an intermediary indicator layer between the breath sample and the optical sensor. This layer contains ammonia-reactive chemical groups that selectively interact with ammonia molecules while being insensitive to water, thereby mediating the detection process to eliminate water interference while maintaining operational simplicity.
Solution Approach 2:
The patent creates a localized sensing environment within the indicator layer where chemical reactions occur selectively. The indicator layer is engineered with specific chemical properties that create a microenvironment favorable for ammonia detection while excluding water interference, allowing direct breath analysis without complex preprocessing.
3Measurement precision
If ammonia concentration is increased for easier detection, then detection sensitivity improves, but physiological relevance is lost
Solution Approach 1:
The patent changes the parameter of the sensing mechanism rather than the sample. By modifying the indicator layer's chemical composition to be highly sensitive to trace ammonia concentrations, the system can detect physiologically relevant low concentrations (parts per billion level) without concentrating the breath sample, thereby maintaining both sensitivity and physiological relevance.
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
The solution enhances ammonia detection sensitivity and specificity, allowing for accurate measurement in clinical, field, or home settings, while minimizing interference from water, thus improving the ability to detect ammonia in breath samples effectively.
Implementation Method 1
contacting the conditioned breath sample with an interactant that interacts with the ammonia in the conditioned breath sample, wherein the interaction causes a change in an optical characteristic in relation to the amount of the ammonia in the breath sample
Data Source
AI summary
A method is provided for sensing ammonia in a breath sample. The method comprises conditioning the breath sample so that the conditioned breath sample has a relative humidity greater than a relative humidity corresponding to a first inflection point of a downwardly concave lowest ammonia iso-concentration curve. It also comprises contacting the conditioned breath sample with an interactant that interacts with the ammonia in the conditioned breath sample, wherein the interaction causes a change in an optical characteristic in relation to the amount of the ammonia in the breath sample. It further comprises using the change in the optical characteristic to sense the ammonia in the breath sample. Related apparatuses are also provided.