Gradient Accuracy Measurement in Liquid Chromatography
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Solution Overview
Problem
The measurement of accuracy in sending liquid in a gradient in an LC system is hindered when a separation column is present on the analysis flow path, as caffeine is held in the column, preventing proper evaluation of gradient accuracy, necessitating column detachment for accurate concentration measurements, which disrupts the sequential execution of all performance evaluation items.
Innovation Solution
A method using a liquid sender that adjusts the concentration of a mobile phase made from two solvents, where one solvent does not include the detected component and the other solvent includes it, preventing component retention in the separation column, allowing for accurate gradient concentration measurement even with the column on the flow path, enabling successive execution of all measurement items.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separation column is provided on the analysis flow path, then the LC system can perform separation and analysis functions, but the accuracy of concentration in sending liquid in the gradient cannot be properly evaluated due to component retention in the column
Solution Approach 1:
The patent changes the chemical composition parameters of the mobile phase by using an organic solvent containing liquid that does not include the component to be detected as the first solvent, and an organic solvent containing liquid that includes the component to be detected but is adjusted to have a concentration that prevents the separation column from actually holding the component as the second solvent. This parameter change allows accurate measurement without column detachment.
Solution Approach 2:
The patent introduces a specific mobile phase composition as an intermediary medium that allows the separation column to remain in place while preventing component retention. The mobile phase acts as a mediator that enables both the separation column to function and the gradient accuracy measurement to be accurate simultaneously.
2Measurement precision
If the separation column is detached from the analysis flow path to measure gradient accuracy, then accurate concentration measurement is achieved, but the sequential execution of multiple measurement items is disrupted
Solution Approach 1:
By changing the mobile phase composition to use organic solvents with specific properties (first solvent without the detected component, second solvent with the component at a concentration that prevents retention), the system achieves accurate gradient concentration measurement without requiring column detachment, thus maintaining sequential execution of multiple measurement items.
Solution Approach 2:
The patent creates a universal mobile phase composition that serves multiple functions: it allows the separation column to remain in place, prevents component retention, enables accurate gradient accuracy measurement, and maintains system configuration for other measurement items like noise and drift measurements.
3Device complexity
If the same mobile phase composition is used for all measurements, then the separation column can remain in place, but accurate gradient concentration measurement cannot be performed due to component retention
Solution Approach 1:
The patent specifies precise parameter changes in the mobile phase composition: using an organic solvent containing liquid that does not include the component to be detected as the first solvent, and an organic solvent containing liquid that includes the component to be detected but is adjusted to have a concentration that prevents the separation column from actually holding the component as the second solvent. These parameter changes enable accurate measurement while maintaining system stability.
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 allows for accurate measurement of gradient concentration without column detachment, enabling the sequential execution of noise, drift, and reproducibility measurements, enhancing the overall performance evaluation of the LC system.
Implementation Method 1
a liquid sender that is capable of adjusting a concentration of a second solvent in a mobile phase made of a first solvent and the second solvent to a predetermined setting value
Implementation Method 2
an actual concentration of the second solvent in the mobile phase that is sent at each setting value is found based on a detection signal of the detector
Implementation Method 3
a separation column and a detector on an analysis flow path through which the mobile phase from the liquid sender flows
Data Source
AI summary
An organic solvent containing liquid that does not include a component to be detected by a detector is used as a first solvent, and an organic solvent containing liquid that includes the component to be detected and is adjusted to have a concentration of an organic solvent that prevents a separation column from actually holding the component to be detected is used a second solvent. Further, a mobile phase is sent while a setting value of a concentration of the second solvent in the mobile phase is changed over time with the separation column provided on an analysis flow path, and an actual concentration of the second solvent in the mobile phase is found based on a detection signal of the detector when the mobile phase is sent at each setting value.