Spectrometer Pathlength Deviation Correction Using Water Absorption Bands
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Solution Overview
Problem
Spectrometers in the food industry face challenges with cuvette pathlength deviations due to wear and tear, leading to unstable calibration and the need for frequent recalibration, especially when standardization samples are difficult to access or introduce.
Innovation Solution
A method to determine and correct cuvette pathlength deviations using the difference between specific wavenumbers associated with a reference liquid, such as water, eliminating the need for a standardization sample and allowing for pathlength correction based on individual sample spectra, even in regions with substantial absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standardization samples are used to calibrate spectrometers, then calibration accuracy is improved, but the complexity of operation increases and access is required to introduce samples
Solution Approach 1:
The spectrometer performs self-calibration by automatically detecting pathlength deviations through analysis of the sample spectrum itself. The system identifies characteristic absorption bands (e.g., water bands at 1640 cm⁻¹ and 6300 cm⁻¹) and calculates deviations without requiring external standardization samples or manual intervention, thereby maintaining calibration accuracy while eliminating the need for sample introduction and complex calibration procedures
Solution Approach 2:
The patent uses characteristic absorption bands of the sample (such as water bands) as an intermediary to indirectly determine pathlength deviations. Instead of directly measuring pathlength with standardization samples, the system uses the sample's own spectral features as a reference to calculate deviations, enabling calibration without external standards
2Reliability
If frequent recalibration is performed to maintain stable calibration, then measurement reliability is improved, but productivity decreases due to time loss
Solution Approach 1:
The system continuously monitors pathlength deviations during normal operation by analyzing the spectral features of each sample. Instead of performing discrete recalibration cycles, the calibration correction is applied continuously and automatically with each measurement, maintaining reliable calibration without interrupting the measurement workflow and maximizing productivity
Solution Approach 2:
The system implements feedback by continuously comparing the measured spectral features against expected reference values and automatically adjusting the pathlength deviation correction. This closed-loop approach ensures calibration stability is maintained dynamically without requiring manual intervention or stopping measurements for recalibration
3Ease of operation
If cuvette pathlength deviations are not corrected, then ease of operation is maintained, but measurement precision deteriorates over time
Solution Approach 1:
The spectrometer automatically detects and corrects pathlength deviations using the sample's own spectral features without requiring user intervention. The system identifies characteristic absorption bands, calculates the deviation from reference values, and applies correction factors automatically, thereby maintaining measurement precision while keeping the operation simple and uninterrupted
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 stabilizes spectrometer calibration by accurately correcting for cuvette pathlength deviations without requiring a standardization sample, enabling reliable measurements and reducing the need for frequent recalibration, especially in in-line processes where access is limited.
Implementation Method 1
a detector which is arranged to detect the intensity of a received electromagnetic radiation at different wavenumbers
Implementation Method 2
measures the intensity of electromagnetic radiation which is transmitted through, or reflected by, a sample
Data Source
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AI summary
A method of determining a pathlength deviation of a sample (610), the method comprising: exposing the sample (610) to electromagnetic radiation at a plurality of wavenumbers, determining electromagnetic absorption in the sample (610) at the plurality of wavenumbers, determining a first wavenumber associated with a first absorption level of an absorption band and a second wavenumber associated with a second absorption level of the absorption band, wherein the second wavenumber is different from the first wavenumber, determining a difference between the first wavenumber and the second wavenumber, and determining the pathlength deviation based on the difference.