Liquid Chromatograph Flow Path Cleaning via Composition Change
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Solution Overview
Problem
In liquid chromatography, carry-over of previous samples can occur during subsequent analyses, leading to unreliable results and requiring extensive cleaning procedures, which decrease throughput performance.
Innovation Solution
The implementation of a liquid chromatograph with a cleaning solution supply flow path that combines with the mobile phase to temporally change the flow path composition, and a pressure release mechanism to decrease internal pressure, enhancing carry-over elimination efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple blank injections are performed to eliminate carry-over, then carry-over elimination is improved, but analysis throughput deteriorates due to increased downtime
Solution Approach 1:
The patent changes the chemical composition parameter of the mobile phase by introducing a cleaning solution with different properties (stronger solvent capability) to enhance carry-over elimination. This allows more effective cleaning with fewer blank injections, thereby improving throughput while maintaining reliability.
Solution Approach 2:
The cleaning solution acts as an intermediary substance between the sample analysis and the next analysis. It is introduced into the flow path to chemically clean residual samples from the system, enabling more effective carry-over prevention without requiring multiple repeated blank injections.
2Reliability
If cleaning solution alone is used for flow path cleaning, then cleaning effectiveness is improved, but the number of blank injections required increases
Solution Approach 1:
The patent merges the cleaning solution with the mobile phase in a combined flow path configuration. This allows the cleaning solution to be delivered through the existing mobile phase delivery system, combining cleaning functionality with the standard analysis workflow and reducing overall cleaning time without sacrificing effectiveness.
Solution Approach 2:
The cleaning solution is designed to serve multiple functions: it cleans the flow path, conditions the column, and can be used during both analysis and post-analysis periods. This multi-functionality reduces the need for separate dedicated cleaning steps and minimizes total cleaning time.
3Stability of the object's composition
If mobile phase is continuously supplied to maintain high pressure, then flow stability is improved, but carry-over elimination deteriorates due to strong adhesion of remaining components
Solution Approach 1:
The patent implements periodic pressure reduction cycles where the mobile phase supply is temporarily interrupted or reduced to lower pressure. This periodic action allows residual components to detach from the flow path walls more easily, improving carry-over elimination while maintaining flow stability during normal operation through resumed mobile phase supply.
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 significantly reduces the number of blank injections required for carry-over elimination, shortening the cleaning time and improving the overall throughput of the liquid chromatograph.
Implementation Method 1
supplying a mobile phase and a cleaning solution having properties different from those of the mobile phase to the analysis flow path and/or the sampling flow path to temporally change the composition of liquid flowing in the analysis flow path and/or the sampling flow path
Implementation Method 2
when the internal pressure of the flow path is temporarily decreased, the force of sticking the remaining component to the flow path wall surface is weakened
Data Source
AI summary
A liquid chromatograph includes at least one mobile phase supply flow path (6; 42), at least one cleaning solution supply flow path (8; 44) joining the mobile phase supply flow path (6; 42), an analysis flow path (4) provided with a separation column (14), a sampling flow path (2) provided, at a tip end thereof, with a sampling needle (12), a switcher (10; 26) including a high-pressure valve (10) having an injection port (16) and configured to switch a flow path configuration of the liquid chromatograph between a loading state in which the analysis mobile phase supply flow path (6) and the analysis flow path (4) are connected in a fluid manner without the sampling flow path (2) and an injecting state in which the sampling flow path (2) is interposed between the analysis mobile phase supply flow path (6) and the analysis flow path (4) when a tip end of the needle (12) is inserted into the injection port (16), and a controller (50) configured to execute, when a predetermined condition is satisfied, the cleaning operation of supplying the mobile phase and the cleaning solution to the analysis flow path (4) and/or the sampling flow path (2) to temporally change the composition of liquid flowing in the analysis flow path (4) and/or the sampling flow path (2).