Stable Liquid Membranes for Microextraction
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Solution Overview
Problem
Current liquid phase microextraction (LPME) techniques face challenges with unstable liquid membranes that have limited lifetimes, making them unsuitable for extended use in sample preparation for analytical instruments, particularly in biological and environmental samples.
Innovation Solution
Development of stable liquid membranes supported on porous polymeric substrates, specifically using fatty acid esters, vegetable oils, silicone oils, and nitroarylalkylethers, which can be stored for at least 30 days and maintain extraction performance, allowing for prolonged use without significant loss of analyte recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional liquid phase microextraction (LPME) techniques are used, then analyte extraction can be performed, but the liquid membranes have limited lifetimes and are unstable
Solution Approach 1:
The patent uses porous hollow fiber membranes as a support structure for the liquid membrane phase. The porous substrate provides mechanical stability and structural integrity to the liquid membrane, preventing its degradation and extension its lifetime while maintaining extraction reliability over extended periods.
Solution Approach 2:
The invention creates a composite structure combining a porous solid support (hollow fiber membrane) with a liquid membrane phase (organic solvent). This composite material integrates the mechanical stability of the solid substrate with the extraction capabilities of the liquid phase, resolving the contradiction between stability and lifetime.
2Reliability
If large volumes of extraction solvent are used in liquid-liquid extraction (LLE), then quantitative extraction can be achieved, but additional concentration steps are required and time increases
Solution Approach 1:
The patent extracts only the essential function of LLE (analyte partitioning) while removing the excessive solvent volume requirement. By using a supported liquid membrane with controlled, minimal volume, the system achieves quantitative extraction without the need for additional concentration steps, eliminating time loss.
Solution Approach 2:
The liquid membrane is configured as a thin film within the hollow fiber structure, minimizing the volume of extraction solvent required while maintaining sufficient capacity for analyte partitioning. This thin film approach enables quantitative recovery without requiring large solvent volumes that would necessitate subsequent concentration.
3Quantity of substance
If solid-phase extraction (SPE) is used, then analyte concentration can be achieved, but maximum concentration enhancement is limited to a factor of 4
Solution Approach 1:
The patent employs a liquid membrane phase within the hollow fiber that leverages fluid dynamics and partitioning principles to achieve high concentration factors. The liquid membrane allows for greater analyte uptake capacity compared to solid-phase adsorbents, enabling concentration enhancement factors of 10 to 100 or more.
Solution Approach 2:
The invention changes the phase state from solid (SPE) to liquid (LPME), fundamentally altering the extraction mechanism. This parameter change enables significantly higher analyte concentration factors by utilizing the superior partitioning and solvation capabilities of the liquid membrane phase compared to solid-phase adsorption.
4Quantity of substance
If liquid-liquid microextraction (LLME) is used, then analyte enrichment can be achieved, but the liquid membrane is unstable and has limited lifetime
Solution Approach 1:
The porous hollow fiber substrate provides structural support that stabilizes the liquid membrane phase, preventing its degradation and extension its operational lifetime while maintaining high analyte enrichment capabilities through the liquid-liquid partitioning mechanism.
Solution Approach 2:
By combining the porous solid support with the liquid membrane phase, the invention creates a composite structure that integrates the enrichment capability of LLME with the stability and longevity of the supported membrane system, resolving the contradiction between enrichment and stability.
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 stable liquid membranes enable efficient and prolonged extraction of analytes from biological and environmental samples, achieving high enrichment factors and maintaining extraction performance over extended storage periods, thus addressing the limitations of previous LPME methods.
Implementation Method 1
uncharged analytes are first equilibrated with an intermediate organic phase, then trapped in an aqueous acceptor phase
Implementation Method 2
a liquid membrane formed from an organic phase on a porous polymeric substrate
Data Source
AI summary
The invention provides devices and methods for performing liquid phase microextraction of at least one analyte from an aqueous sample, wherein the device comprises a liquid membrane comprising a fatty acid ester, a vegetable oil, a silicone oil, a nitroarylalkylether, or mixtures thereof, and an optional carrier, supported on a porous polymeric substrate. In a preferred embodiment, the porous polymeric substrate is a hollow fiber. The devices and methods for preparing them provide stable liquid membranes for performing liquid phase microextraction, where the membranes can be stored for 30, 60 or 90 days prior to use.