Autosampler Flow Path Switching Mechanism for Gradient Analysis
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Solution Overview
Problem
High-pressure gradient analysis in liquid chromatography is hindered by a large 'delay capacity' that increases analysis time, particularly at low flow rates, as it takes longer for the gradient to be reflected in the composition of the moving-phase liquid in the analysis column, slowing down sample elution.
Innovation Solution
An autosampler with a flow path switching mechanism that connects solvent delivery flow paths directly to the analysis flow path without a mixer, allowing for a 'loading' mode that bypasses the sample loop during gradient feeding, reducing the delay capacity and enabling faster reflection of gradient changes in the moving-phase liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a mixer is used to mix solvents in high-pressure gradient analysis, then the solvents can be mixed and fed to the analysis column, but the delay capacity increases and analysis time extends
Solution Approach 1:
The invention extracts and removes the mixer from the gradient analysis system. By eliminating the mixer component, the patent achieves solvent mixing through direct flow path connection and pressure-driven mixing in the analysis column, thereby removing the source of delay capacity while maintaining gradient analysis functionality.
Solution Approach 2:
The flow path switching mechanism is designed to perform multiple functions: it controls sample injection, manages solvent delivery, and enables gradient analysis without requiring a separate mixer. This multi-functional design integrates the mixing capability into the existing flow path structure, eliminating the need for additional mixing components that would increase delay capacity.
2Measurement precision
If the flow rate of the feeding pump is reduced to 100μL/min or less, then the sample introduction precision is improved, but the analysis time increases noticeably due to increased delay capacity
Solution Approach 1:
By removing the mixer from the system, the patent eliminates the primary source of delay capacity. This allows the system to maintain low flow rates (100μL/min or less) for precise sample introduction without suffering from the time delays that would normally occur in the mixer, thus preserving both precision and productivity.
Solution Approach 2:
The flow path switching mechanism prepares the system in advance by directly connecting the solvent delivery flow paths to the analysis column before gradient feeding begins. This preliminary configuration ensures that when low flow rates are used for precise sample introduction, the gradient can be reflected immediately in the analysis column without waiting for mixer processing.
3Ease of manufacture
If a mixer is included in the gradient analysis system, then solvent mixing is achieved, but the delay capacity from mixer to analysis column increases
Solution Approach 1:
The invention directly extracts the mixer component from the gradient analysis system. By removing this stationary object, the patent eliminates the physical distance and volume that constitute delay capacity, while maintaining solvent mixing capability through pressure-driven direct injection into the analysis column.
Solution Approach 2:
The patent uses hydraulic pressure from the feeding pump to achieve solvent mixing and delivery directly to the analysis column without mechanical mixing components. The pressure-driven flow path switching mechanism enables solvent mixing through controlled flow dynamics rather than mechanical agitation, eliminating the need for a physical mixer that would add delay capacity.
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 configuration significantly reduces the analysis time by minimizing the delay between solvent delivery and analysis, even at low flow rates, allowing for quicker gradient reflection and sample elution in the analysis column.
Implementation Method 1
a syringe pump that sucks and discharges a sample through a needle
Implementation Method 2
an analysis flow path which is provided with an analysis column that separates a sample according to each component
Data Source
AI summary
An autosampler is provided with a needle, syringe pump, needle drive mechanism, sample loop, and flow path switching mechanism. The flow path switching mechanism has a plurality of solvent delivery flow paths that each deliver a different solvent, an analysis flow path that is in communication with an analysis column for separating a sample, and a plurality of connection ports to which the ends of the sample loop are individually connected, and switches, by switching the Connection state between the connection ports, to either a loading mode for connecting all the solvent delivery flow paths to the analysis flow path without interposing the sample loop or an injecting mode for interposing the sample loop between all the solvent delivery flow paths and the analysis flow path.