Differential Photometric Analyzer Non-Linearity Compensation
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Solution Overview
Problem
Existing analytical instruments face challenges in accurately measuring constituents of interest due to complex and poorly understood instrument responses, leading to biases in measurements that affect accuracy.
Innovation Solution
The method involves using a system with multiple analyzers and filters to measure constituents of interest by compensating for instrument biases through differential photometric analysis, where the concentration is calculated by estimating and applying corrections based on current and previous measurements of light attenuation at different wavelengths, allowing for improved accuracy without relying on instrument calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If indirect measurements with assumed functional relationships are used, then measurement simplicity is improved, but measurement accuracy deteriorates when instrument responses are complex and poorly understood
Solution Approach 1:
The patent changes the parameters being measured by simultaneously measuring multiple wavelengths of light absorption. Instead of relying on a single indirect measurement with an assumed functional relationship, the system measures absorption at multiple wavelengths (including reference wavelengths not absorbed by the analyte) to directly capture the complex instrument response characteristics, thereby resolving the contradiction between simplicity and accuracy.
2Measurement precision
If instrument calibration is used to compensate for biases, then measurement accuracy is improved, but the method becomes unreliable when calibration data is unavailable or instruments are modified
Solution Approach 1:
The patent implements a self-service approach where the instrument measures its own response characteristics by using reference wavelengths that are not absorbed by the analyte. These reference measurements allow the system to self-correct for instrument biases, drift, and modifications without requiring external calibration standards or stored calibration data, thereby maintaining both accuracy and reliability.
3Measurement precision
If derivatives of measured values are used to compensate for non-linearities, then measurement accuracy is improved, but measurement stability deteriorates due to amplification of noise
Solution Approach 1:
The patent introduces reference wavelength measurements as an intermediary that mediates between the raw absorption measurements and the final concentration calculation. By measuring absorption at reference wavelengths that are not affected by the analyte, the system obtains a stable reference signal that can be used to correct for instrument non-linearities without requiring differentiation of the analyte absorption signal, thus avoiding noise amplification while maintaining accuracy.
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 enhances measurement accuracy by accounting for non-linearities and biases, providing a more precise estimation of constituent concentrations, even in instruments with complex responses.
Implementation Method 1
at least one filter to collect constituents of interest in a sample
Implementation Method 2
Said first attenuation and said second attenuation can result from absorption of light at two or more wavelengths through said first filter portion and said second filter portion, respectively
Implementation Method 3
a differential photometric analyzer
Data Source
Figure 1~2
Figure 3~4
AI summary
An apparatus and method are presented for mesuring constituents in a sample. The apparatus includes two or more similar analyzers (112, 114), with the output of the analyzers combined to provide improved measurements. The apparatus may be, for example, a differential photometric analyzer, such as the AETHALOMETER®. The apparatus includes filters (121, 123) for accumulating constituents in a sample flowing through volumes (113, 115) respectively, sensors (113, 115) for measuring light absorption within the filters, and a processor (201) programmed to accept an instrument constant determined at low filter loadings and use the constant to compensate for non-linear instrument responses. A method is also presented for conditioning the filters before use.