Sample Analysis Apparatus Using Reference Substance for LOD Estimation
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Solution Overview
Problem
Existing sample analysis methods require complex and time-consuming processes to calculate the limit of detection (LOD) and limit of quantitation (LOQ) for multiple target compounds, which becomes costly and labor-intensive, especially when the number of compounds increases and sample analysis apparatus conditions change over time due to contamination or degradation.
Innovation Solution
A sample analysis apparatus that stores response factors for various substances, allowing for the estimation of analysis limits like LOD and LOQ without performing extensive analysis on target compounds, by using a reference substance to calculate signal strength, SN ratio, and relative standard deviation, and preparing calibration curves based on measured signal strength values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods (A, B, or C) are used to calculate LOD and LOQ for each target compound, then measurement reliability is ensured, but the process becomes extremely complicated and time-consuming when the number of target compounds increases
Solution Approach 1:
The patent introduces a reference substance as an intermediary to indirectly determine LOD and LOQ for target compounds. Instead of directly analyzing each target compound (which is complex), the system analyzes the reference substance and uses the pre-stored response factor to calculate the analysis limits for target compounds. This mediator approach simplifies the process while maintaining reliability through the established response factor relationship.
Solution Approach 2:
The response factor between the reference substance and target compounds is determined and stored in advance before the actual analysis. This preliminary action allows the system to quickly calculate LOD and LOQ for multiple target compounds without repeating the full calibration process, significantly reducing complexity when analyzing multiple compounds while ensuring measurement reliability through pre-validated response factors.
2Reliability
If standard samples are prepared and analyzed repeatedly to check LOD and LOQ periodically, then measurement reliability is maintained, but a large amount of time and effort is required
Solution Approach 1:
The reference substance serves as a mediator for periodic reliability checks. Instead of preparing and analyzing standard samples for each target compound periodically (which is time-consuming), the system periodically analyzes the reference substance and uses the stored response factor to update LOD and LOQ calculations for all target compounds, dramatically reducing the time required for periodic verification while maintaining measurement reliability.
3Measurement precision
If extensive analysis on target compounds is performed to calculate LOD and LOQ, then accurate analysis limits are obtained, but costs increase significantly
Solution Approach 1:
The reference substance acts as a cost-effective intermediary. Instead of performing extensive analysis on expensive target compound standard samples to determine LOD and LOQ, the system analyzes the reference substance (which can be less expensive or reused) and calculates target compound analysis limits using the pre-determined response factor, reducing costs while maintaining measurement precision through the validated response relationship.
Solution Approach 2:
The system creates a computational model (copy) of the target compound analysis through the reference substance analysis. By using the stored response factor, the system replicates the analytical relationship without physically analyzing the target compound repeatedly, obtaining accurate LOD and LOQ values while minimizing consumption of expensive target compound standards.
4Adaptability or versatility
If the number of target compounds is increased, then comprehensive analysis capability is improved, but the work becomes very complicated and expensive
Solution Approach 1:
The reference substance provides a universal solution for determining LOD and LOQ across multiple different target compounds. Instead of developing separate analysis procedures for each compound (which increases complexity with more compounds), the single reference substance with its pre-determined response factor serves all target compounds, enabling comprehensive analysis capability while keeping the workflow simple and scalable to any number of analytes.
Data Source
AI summary
A response factor that is a signal strength ratio with respect to a reference compound for various compounds is previously stored in a response factor storage (22). When an operator instructs to estimate an analysis limit value, a measurement unit (1) performs GC-MS analysis on a sample containing the reference compound a plurality of times under control of an analysis controller (3). A signal strength calculator (23) obtains a signal strength value of the reference compound based on an analysis result of the measurement unit (1), a relative strength calculator (24) calculates a relative standard deviation from the plurality of measured signal strength values, and calculates the relative standard deviation of a target compound from the response factor of the target compound read from the response factor storage (22). An analysis limit value estimator (25) estimates a limit of detection (LOD) and the like from the relative standard deviation of the target compound by a known method, and displays the LOD on a display (6). Consequently, the analysis limit value can simply be obtained without actually measuring the target compound.