Liquid Chromatograph Flow Switching for Mixer Optimization
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Solution Overview
Problem
Liquid chromatographs face challenges in achieving high sensitivity analysis due to broadened sample bands from large sample injections and the complexity of switching between online concentration and direct analysis flow configurations, along with issues in solvent mixing at varying flow rates.
Innovation Solution
A liquid chromatograph with a flow passage switching mechanism using multi-port valves and mixers of varying capacities to selectively form different flow passages for normal and concentration analyses, ensuring optimal solvent mixing at any flow rate, thereby improving analytical reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single mixer is used in the liquid chromatograph, then the device complexity is reduced, but the mixing performance deteriorates when flow rate changes occur
Solution Approach 1:
The system dynamically switches between a first mixer and a second mixer based on the flow rate of the mobile phase. When the flow rate exceeds a predetermined threshold, the system switches to the second mixer with different mixing characteristics, thereby adapting to changing operating conditions and maintaining reliable mixing performance across varying flow rates.
Solution Approach 2:
The invention changes the mixing parameters by switching between mixers with different capacities and mixing characteristics. The first mixer is optimized for lower flow rates while the second mixer is optimized for higher flow rates, allowing the system to maintain optimal mixing performance across a wide range of flow rates by selecting the appropriate mixer for each operating condition.
2Reliability
If a mixer with large capacity is used, then mixing performance at high flow rates is improved, but delay time increases at low flow rates
Solution Approach 1:
The system dynamically selects the appropriate mixer based on the current flow rate. At low flow rates, the first mixer with smaller capacity is used to minimize delay time. When the flow rate increases beyond a predetermined value, the system switches to the second mixer with larger capacity to ensure adequate mixing performance, thereby optimizing the balance between mixing effectiveness and time efficiency across different operating conditions.
3Loss of time
If a mixer with small capacity is used, then delay time at low flow rates is reduced, but mixing performance deteriorates at high flow rates
Solution Approach 1:
The system employs dynamic switching between two mixers based on flow rate conditions. The first mixer with smaller capacity is used for low flow rate operations to minimize delay time, while the second mixer with larger capacity is activated when flow rate exceeds a predetermined value to ensure sufficient mixing performance, thereby resolving the contradiction between speed and mixing effectiveness.
4Adaptability or versatility
If flow passage configuration is changed for direct analysis, then recovery rate determination is enabled, but operation complexity and time increase
Solution Approach 1:
The flow passage system is designed with multi-functionality to support both online concentration analysis and direct analysis modes. By incorporating switching valves and a trap column that can be integrated into the flow path, the system enables users to perform both types of analysis without requiring separate flow passage configurations, thereby simplifying operation while maintaining versatility.
Solution Approach 2:
The system prepares the flow passage configuration in advance by incorporating all necessary components (switching valves, trap column) into a single integrated design. This preliminary arrangement allows the system to switch between analysis modes through simple valve operations rather than requiring complex reconfiguration of the entire flow passage, thereby reducing operational complexity and time.
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
Enables efficient solvent mixing across a wide range of flow rates, reducing delays and improving analytical sensitivity and reproducibility without complications in flow passage configuration changes.
Implementation Method 1
a mixer unit provided downstream of the mobile-phase-sending-unit to mix solvents sent from the mobile-phase-sending-unit
Implementation Method 2
a trapping column for concentrating a dilute sample and allowing the sample to be analyzed in a concentrated state
Data Source
AI summary
A liquid chromatograph having a flow passage switching mechanism for switching among a normal analysis flow passage formed by connecting a mobile-phase-sending-unit, a second mixer having a large capacity, a sample injection portion, an analysis column and a detector in this order, a concentration flow passage formed by connecting a concentration liquid sending unit for sending a liquid for transferring a sample to be concentrated, the second mixer, the sample injection portion and a trapping column in this order, and a concentration analysis flow passage formed by connecting the mobile-phase-sending-unit, a first mixer having a smaller capacity than the second mixer, the trapping column, the analysis column and the detector in this order so that any one of the three flow passages is selectively formed, The mobile-phase-sending-unit is set so that the flow rate of a mobile phase becomes smaller when the concentration analysis flow passage is selected than when the normal analysis flow passage is selected.