Liquid Chromatography Fraction Collector Wash Solvent Flush
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Solution Overview
Problem
Conventional fraction collectors in liquid chromatography systems suffer from cross-fraction contamination due to residual liquid in the collection tube, leading to reduced sample recovery and contamination of subsequent fractions.
Innovation Solution
A four-port fraction valve system that diverts the liquid chromatography system flow to a collection tube during a fraction collection window and uses a wash solvent to flush out the remaining liquid at the end of the window, minimizing cross-contamination and increasing the collected fraction volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the diverter valve is actuated to direct system flow to a collection vessel at the beginning of a time window and later de-actuated at the end of the time window, then fraction collection is achieved, but cross-fraction contamination occurs due to liquid retained in the collection tube
Solution Approach 1:
A wash solvent is introduced through the collection tube before the next fraction collection begins, flushing out residual liquid from the previous fraction. This preliminary cleaning action prevents cross-contamination while ensuring complete sample recovery from the previous fraction.
Solution Approach 2:
A wash solvent is used as an intermediary substance to clear the collection tube between fraction collections. The wash solvent temporarily occupies the collection tube to displace residual fraction liquid, then is discarded, leaving the tube clean for the next fraction without contaminating it.
2Productivity
If the collection tube retains liquid from the end of the previous collection window, then the diverter valve can be quickly switched for the next fraction, but sample recovery is reduced and contamination occurs
Solution Approach 1:
The wash solvent is introduced immediately after the diverter valve switches to waste position, before the next fraction collection begins. This timing allows rapid clearing of the collection tube without delaying the next fraction collection, maintaining high productivity while ensuring complete sample recovery.
Solution Approach 2:
The system maintains continuous operation by introducing the wash solvent during the brief interval when the diverter valve is switching positions. This keeps the collection tube ready for the next fraction without interruption to the overall fraction collection process.
3Adaptability or versatility
If a conventional diverter valve is used to redirect flow between waste channel and collection vessel, then fraction collection is enabled, but liquid remains in the collection tube causing contamination
Solution Approach 1:
The collection tube serves multiple functions: collecting fraction liquid during the fraction collection window and being flushed by wash solvent during the switching interval. This multi-functionality allows the same tube to handle both fraction collection and self-cleaning without requiring separate components.
Solution Approach 2:
The wash solvent acts as an intermediary that temporarily flows through the collection tube to displace residual fraction liquid. This intermediary substance enables the collection tube to transition from one fraction to the next without retaining contamination, while the diverter valve maintains its fraction collection capability.
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 solution effectively reduces cross-fraction contamination and enhances sample recovery by ensuring that each fraction is collected with minimal contamination from previous fractions, improving the accuracy and purity of subsequent collections.
Implementation Method 1
a flow of wash solvent is provided to the collection tube to dispense at least a portion of a liquid remaining in the collection tube
Data Source
AI summary
Described are a fraction collector and a method of fraction collection for a liquid chromatography system. The method includes diverting a liquid chromatography system flow from a waste channel to a collection tube at a start of a fraction collection window and collecting the system flow dispensed from the collection tube during the fraction collection window. At the end of the window, the system flow is diverted to the waste channel and a flow of a wash solvent is provided to the collection tube to dispense liquid remaining in the collection tube at the end of the window from the collection tube. The method can increase the amount of the collected fraction and can reduce or eliminate cross-contamination of a subsequently collected fraction. The method is useful for analytical scale applications where the collected fractions may have volumes defined by a limited number of drops dispensed from the collection tube.