Optical Path Length Determination Using Certified Reference Materials
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Solution Overview
Problem
Existing methods for determining optical path length, particularly in small volumes, lack traceability and accuracy, making them unsuitable for ISO-compliant protocols and prone to contamination and noise in biotechnology and pharmaceutical research.
Innovation Solution
A method using certified reference materials in high-accuracy cuvettes with specified path lengths and absorbance measurements at multiple wavelengths to determine the optical path length of a sample, ensuring traceable and precise measurements by validating the results against ISO standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods for determining optical path length are used, then the measurement can be performed, but the accuracy and traceability are insufficient
Solution Approach 1:
The patent introduces certified reference materials (CRMs) with known path lengths and absorbance values as intermediaries to bridge the measurement system to traceable standards. By measuring the absorbance of CRMs with known path lengths and using these as calibration references, the unknown sample path lengths can be determined with traceability to national or international standards, resolving the contradiction between measurement capability and traceability.
Solution Approach 2:
The patent utilizes the Beer-Lambert law relationship between absorbance, path length, and concentration to establish a mathematical model. By measuring absorbance at multiple wavelengths and using the known absorbance values of certified reference materials, the system calculates unknown path lengths through parameter relationships, achieving both accuracy and traceability simultaneously.
2Measurement precision
If certified reference materials and high-accuracy cuvettes are used, then traceability and accuracy are improved, but device complexity increases
Solution Approach 1:
The patent employs certified reference materials that serve multiple functions: they act as calibration standards, provide traceability links, and enable validation of measurement systems. The same CRMs are used across different measurement scenarios, allowing a single reference system to support multiple measurement requirements without proportionally increasing complexity.
Solution Approach 2:
The patent uses certified reference materials as standardized copies with known properties. Instead of requiring complex direct measurement of absolute path lengths, the system uses replicated reference standards with predetermined values, simplifying the measurement process while maintaining traceability through the known characteristics of the reference copies.
3Measurement precision
If multiple wavelength measurements are performed, then accuracy is improved, but measurement time increases
Solution Approach 1:
The patent performs absorbance measurements at multiple wavelengths continuously and systematically, using the Beer-Lambert law relationships to calculate path lengths from the spectral data. By integrating multiple wavelength measurements into a cohesive analytical sequence rather than separate steps, the system achieves high accuracy while minimizing total measurement time through efficient data collection and processing.
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 method achieves 2-3 orders of magnitude higher accuracy and provides fully traceable results, reducing contamination and noise, and is faster than prior art, making it suitable for small sample volumes in biotechnology and pharmaceutical research.
Implementation Method 1
absorbance of the certified reference material is measured to obtain a first absorbance measurement for the first specified path length; absorbance of the certified reference material is then measured for a second path length to obtain a second absorbance measurement
Data Source
AI summary
A for traceably determining an unknown optical path length of a sample in an optical measuring device comprises the steps of: providing a drop analyzer connected to a standard spectrophotometer; providing a certified reference material contained in first and second closed high accuracy cuvettes; measuring absorbance of the certified reference material to obtain a first absorbance measurement for the first specified path length; measuring absorbance of the certified reference material for a second path length to obtain a second absorbance measurement; using a dropping device to drop a specified volume of the solvent on an optical surface so that the path length of the specified volume can be determined by reference to the first and second absorbance measurement; and using the dropping device to drop the same volume of sample as the specified volume of solvent on the optical measuring device.