Sample Injector Switching Valve for Low-Dead-Volume LC
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Solution Overview
Problem
Existing liquid chromatography systems face challenges in high-throughput applications requiring flexible injection conditions, such as varying sample volumes and flow rates, with inefficiencies in washing processes, increased dead volume, and sample carryover, particularly for small sample volumes.
Innovation Solution
A simplified liquid chromatography system with a single high-pressure switching valve and a zero or essentially zero-dead-volume connection design, utilizing a high-precision metering pump and separate wash pump, enabling flexible and precise sample injection with minimal dead volume and reduced carryover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sample loops of different inner volume are used to increase flexibility in injection conditions, then adaptability is improved, but device complexity increases and productivity decreases
Solution Approach 1:
The system uses a dynamic valve switching mechanism that allows a single sample loop to be reconfigured for different injection volumes and conditions through rapid valve switching, eliminating the need for multiple fixed-volume loops while maintaining flexibility across different analytical requirements
Solution Approach 2:
A single sample loop is designed to serve multiple functions by combining it with a multi-position valve system that can redirect flow paths to achieve different injection volumes and modes (e.g., full loop injection, partial loop injection, split injection), making one component perform the work of multiple specialized components
2Adaptability or versatility
If multiple sample loops and complex fluidic conduits are used to increase flexibility, then adaptability is improved, but dead volume increases and manufacturing precision becomes more difficult
Solution Approach 1:
The invention extracts and eliminates unnecessary fluidic conduits and connection elements from the traditional multi-loop system, retaining only the essential sample loop and implementing valve-based flow control to achieve flexibility, thereby removing sources of dead volume while preserving adaptability
Solution Approach 2:
The system applies local quality optimization by using low-dead-volume valve configurations and minimizing connection tubing lengths at critical junctions, ensuring that the fluidic pathways have minimal dead volume while still providing multiple flow path options for different injection conditions
3Adaptability or versatility
If multiple sample loops and complex fluidic connections are used to increase flexibility, then adaptability is improved, but reliability decreases due to increased carryover risk
Solution Approach 1:
The invention removes multiple sample loops and complex interconnections that create carryover pathways, retaining a single sample loop with simplified fluidic connections that reduce the number of surfaces and volumes where sample residue can persist between injections
Solution Approach 2:
The system incorporates preliminary washing actions through the valve switching sequence, where wash solvent is directed through the sample loop and fluidic connections between samples to proactively clean surfaces and prevent carryover before the next sample injection, ensuring reliable results
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
The system achieves fast injection cycles, minimizes dead volume, reduces sample carryover, and maintains precision for small sample volumes, while being compact, cost-effective, and compatible with micro-LC systems.
Implementation Method 1
aspirating a sample from a sample container via a sample aspiration needle by generating a negative pressure
Implementation Method 2
pushing the aspirated sample into an LC column via a needle seat by generating a positive pressure
Implementation Method 3
chromatographic separation through an LC column in order for example to separate analytes of interest from matrix components
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An LC system 100 and a respective LC method are disclosed. The LC system 100 comprises an LC switching valve 10 comprising a sample input port 11, an aspiration pump port 12, a needle seat port 13, a waste port 14 leading to a waste 19, an LC pump port 15 and an LC column port 16. The LC system 100 further comprises a sample aspiration needle 5 fluidically connected to the sample input port 11 via a sample receiving conduit 6, an aspiration pump 20 fluidically connected to the aspiration pump port 12 for aspirating a sample 1 via the sample aspiration needle 5 when the sample aspiration needle 5 is inserted into a sample container 2 and when the aspiration pump port 12 is connected to the sample input port 11. The LC system 100 further comprises a needle seat 17 fluidically connected to the needle seat port 13 via a needle seat conduit 18, an LC column 50 fluidically connected to the LC column port 16, and an LC pump 60 fluidically connected to the LC pump port 15, for injecting at least part of the sample 1 aspirated in the sample receiving conduit 6 into the LC column 50 when the sample aspiration needle 5 is seated into the needle seat 17 and when the LC pump port 15 is fluidically connected to the needle seat port 13 and the sample input port 11 is fluidically connected to the LC column port 16. A clinical diagnostic system comprising said LC system 100 is also disclosed.