Auto Sampler with Multi-Position Valve for Injection Accuracy
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Solution Overview
Problem
The existing sample introduction methods for liquid chromatography, particularly the total volume injection method, face challenges in maintaining measurement accuracy during pretreatment processes due to difficulties in cleaning the needle and sample loop, leading to potential sample and mobile phase losses, especially when the cleaning fluid differs from the mobile phase.
Innovation Solution
An automatic sample introduction apparatus is designed with a sample loop, a needle, a measuring pump, multi-position valves, and a retention mechanism, allowing for the total volume injection method while incorporating a cleaning solution system to replace the cleaning fluid with the mobile phase, and a temperature adjusting mechanism for pretreatment reactions, ensuring accurate injection and preventing sample loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the total volume injection method is used, then measurement accuracy is improved, but cleaning difficulty worsens when cleaning fluid differs from mobile phase
Solution Approach 1:
The patent introduces a cleaning solution storage container and switching mechanism as intermediaries to deliver cleaning fluid to the needle and sample loop. This intermediary system enables effective cleaning when cleaning fluid composition differs from mobile phase, resolving the contradiction between maintaining injection accuracy and achieving effective cleaning.
Solution Approach 2:
The patent employs a multi-position valve that can dynamically switch between different modes: normal injection mode, cleaning mode, and rinsing mode. This dynamic switching capability allows the system to adapt to different operational requirements, maintaining both high injection accuracy and effective cleaning capability.
2Ease of manufacture
If the partial injection method is used, then cleaning ease is improved, but measurement accuracy deteriorates
Solution Approach 1:
The patent uses a cleaning solution storage container and switching mechanism as intermediaries to deliver cleaning fluid to the needle and sample loop. This intermediary system enables effective cleaning when cleaning fluid composition differs from mobile phase, resolving the contradiction between maintaining injection accuracy and achieving effective cleaning.
Solution Approach 2:
The patent employs a multi-position valve that can dynamically switch between different modes: normal injection mode, cleaning mode, and rinsing mode. This dynamic switching capability allows the system to adapt to different operational requirements, maintaining both high injection accuracy and effective cleaning capability.
3Adaptability or versatility
If pretreatment is performed before sample introduction, then analysis suitability is improved, but sample loss increases
Solution Approach 1:
The patent performs pretreatment operations (dilution, derivatization, etc.) in advance before the sample is introduced to the chromatograph. The sample loop and needle system is designed to handle these pretreated samples while minimizing losses through proper cleaning and maintenance procedures.
Solution Approach 2:
The patent introduces a cleaning solution storage container and switching mechanism as intermediaries to deliver cleaning fluid to the needle and sample loop. This intermediary system enables effective cleaning when cleaning fluid composition differs from mobile phase, resolving the contradiction between maintaining injection accuracy and achieving effective cleaning.
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 apparatus ensures high measurement accuracy for sample injection, allows for various pretreatment processes like dilution and reactions, and effectively handles different cleaning solutions, reducing sample and mobile phase losses during analysis.
Implementation Method 1
a measuring pump; a multi-position valve; and a first multi-port valve
Implementation Method 2
the multi-position valve includes: a first port connected to the first multi-port valve; a second port connected to a solution of a mobile phase; a third port connected to a cleaning solution
Implementation Method 3
a temperature adjusting mechanism (especially heating) for the second multi-port valve and the retention tube
Data Source
AI summary
A function of automatically performing a pretreatment process on a sample is provided in an auto sampler of a total volume injection method that can realize high measurement accuracy even when an amount of the sample is small. A multi-port valve and a multi-position valve are connected to each other, and a plurality of kinds of cleaning solutions and also a mobile phase are connected to the multi-port valve. By providing a certain volume in a tube connected to a measuring pump for suctioning the sample, the pump can suction a sufficient amount of the cleaning solution or a diluent solution at one suction operation. Consequently, an apparatus according to the invention can deal with the pretreatment such as cleaning and dilution, without repeating the same suction/discharge operations.