Chromatograph Autosampler Flow Path Segmentation
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Solution Overview
Problem
Existing liquid chromatograph autosamplers are inefficient due to lack of cleaning mechanisms during operation, leading to suboptimal performance.
Innovation Solution
A sample injection apparatus with a retention flow path, injection flow path, low-pressure flow path, and state switch valve that allows for efficient sample injection and cleaning by connecting and disconnecting flow paths to facilitate immediate sample delivery to the column and subsequent cleaning of the injection and retention paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional autosampler is used without a cleaning mechanism, then the device complexity is reduced, but the productivity and reliability deteriorate due to sample carry-over and inefficient operation
Solution Approach 1:
The flow path is divided into distinct segments: retention flow path (for sample holding), injection flow path (for sample delivery), and low-pressure flow path (for cleaning). The state switch valve segments the flow paths to enable independent cleaning and injection operations, resolving the contradiction by organizing complexity into functional modules that improve productivity.
Solution Approach 2:
The system performs preliminary cleaning of the retention and injection flow paths using the low-pressure flow path before the next sample injection. This preliminary action prevents sample carry-over and ensures reliable operation, improving productivity while the structured flow path segmentation manages the device complexity.
2Reliability
If the autosampler performs thorough cleaning of flow paths, then the reliability and purity are improved, but the analysis time and productivity may worsen due to additional cleaning steps
Solution Approach 1:
The cleaning operation uses the low-pressure flow path to continuously flush the retention and injection flow paths with mobile phase or cleaning solution during the analysis cycle. This continuous cleaning action maintains reliability and purity without requiring separate cleaning cycles, thus not increasing analysis time.
Solution Approach 2:
The state switch valve dynamically switches between injection mode and cleaning mode based on operational requirements. This dynamic switching enables the system to perform thorough cleaning when needed while maintaining fast injection cycles, resolving the time-reliability contradiction through adaptive operation.
3Productivity
If the sample is delivered immediately to the column, then the productivity is improved, but the risk of sample loss or contamination in the flow path increases
Solution Approach 1:
The injection flow path is segmented and isolated from the retention flow path through the state switch valve. This segmentation allows immediate sample delivery to the column via the injection path while the retention path can be simultaneously cleaned or prepared, preventing sample carry-over and contamination.
Solution Approach 2:
The state switch valve acts as an intermediary that controls the connection between different flow paths. It enables immediate sample delivery by opening the injection path while closing the retention path, and vice versa for cleaning operations, thus preventing harmful interactions between samples and ensuring productivity.
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 use of the autosampler by ensuring immediate sample delivery to the column and thorough cleaning of the injection and retention paths, reducing sample consumption and carry-over, and allowing for faster analysis cycles.
Implementation Method 1
a measuring pump that delivers the sample injected into the downstream analysis flow path
Implementation Method 2
a cleaning pump that delivers the cleaning solution into the retention flow path and the injection flow path through the low-pressure flow path
Data Source
AI summary
An autosampler includes a retention path for injecting a sample into a mobile phase that flows through an analysis path to a column, the retention path including a needle at a downstream end and holding the sample, an injection path including a port at an upstream end for injecting into the analysis path, the sample injected from the needle into the port, a low-pressure path having an upstream end connected to a pump, and a valve that can switch between a first state in which an upstream analysis path and a downstream analysis path are connected and a downstream end of the low-pressure path and an upstream end of the retention path are connected and a second state in which the upstream analysis path and the upstream end of the retention path are connected and the downstream end of the injection path and the downstream analysis path are connected.