Solid Phase Extraction Disk Holder Sealing Design
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Solution Overview
Problem
Conventional solid phase extraction (SPE) filtration disk holders suffer from leakage and inconsistent analyte recovery due to pinched seals, which trap analytes and prevent their extraction during the elution step when using vacuum or positive pressure.
Innovation Solution
The SPE disk is compressed and press-fitted into the basin to form a seal along its thickness, using a resilient construction to prevent deformation, and an O-ring provides a leak-tight seal between the basin closure and the basin, ensuring fluid flow through the disk without trapping analytes at the pinch point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SPE disk is clamped between upper and lower assemblies to ensure a leak-tight seal, then sealing reliability is improved, but analyte recovery deteriorates due to trapped analytes at the pinch point
Solution Approach 1:
The sealing function is extracted from the SPE disk itself and transferred to a separate gasket component. The gasket is placed in a groove on the funnel, creating a seal between the funnel and filter holder without pinching the SPE disk, thus eliminating analyte trapping while maintaining sealing reliability
Solution Approach 2:
The sealing system is segmented into distinct components: a dedicated gasket element separate from the SPE disk. This allows the SPE disk to remain uncompressed while the gasket provides the sealing function, resolving the contradiction between seal integrity and analyte recovery
2Productivity
If vacuum or positive pressure is used to move liquid through the SPE disk, then filtration efficiency is improved, but analyte trapping worsens due to increased force at the pinch point
Solution Approach 1:
The sealing function is extracted from the SPE disk and assigned to a separate gasket component. This eliminates the pinch point created by clamping the SPE disk between assemblies, allowing vacuum or positive pressure to move liquid through the disk without trapping analytes at compression points
Solution Approach 2:
A gasket acts as an intermediary sealing element between the funnel and filter holder. This mediator provides the necessary seal for pressure differential operation without directly contacting or compressing the SPE disk, preventing analyte trapping while maintaining filtration efficiency
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
This design ensures consistent and complete recovery of analytes by preventing leakage and trapping, allowing for thorough extraction and accurate results without residual analytes in the pinched area.
Implementation Method 1
The SPE disk best suited for this press fit seal should be on the order of 3 to 10 mm thick and of a resilient construction to allow the disk to elastically compress or flex as to be pressed into position
Implementation Method 2
An O-ring on the basin closure may provide a seal between the basin and top sealing member
Implementation Method 3
The basic objective of such apparatus is to filter the liquid sample and to selectively adsorb compounds or analytes from the liquid portion onto a sorbent
Data Source
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AI summary
Solid phase extraction (SPE) disks provide the greatest extraction efficiency when the maximum surface area of the disk is exposed to the sample. Such may be accomplished with the present disclosure wherein an SPE disk is secured within a cavity of a disk holder apparatus such that the SPE disk compresses against a side wall defining the cavity and forms a seal therebetween. The disk holder apparatus may be used in an open design for vacuum applications, or in a sealed design with a closure, when using positive pressure to force the sample through the disk. Examples of various configurations for the disk holder apparatus and methods of use are provided.