Asymmetric Sample Vial Design for Capillary Electrophoresis
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Solution Overview
Problem
Conventional sample vials for capillary electrophoresis (CE) instruments require a significant volume of sample for effective injection, leading to waste of expensive or scarce samples, as the capillary and electrode must penetrate the sample, limiting the vial's inner diameter.
Innovation Solution
A non-round, polarized vial design with a first and second fluid chamber, each with a cross-sectional shape exhibiting at most two axes of symmetry, allowing for very small sample volumes to be sampled by CE probes without sacrificing large volume containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional round vials or narrow inserts are used, then the vial can accommodate the capillary and electrode for electrokinetic injection, but a significant volume of sample (20-50 μL minimum) is wasted because the sample cannot be accessed by the probe
Solution Approach 1:
The vial insert transitions from a symmetric circular cross-section to an asymmetric D-shaped or rectangular cross-section. This asymmetry allows the flat side or corner to be positioned against the inner wall of the round vial, enabling the capillary and electrode to penetrate the sample from the curved side without the sample being trapped in inaccessible corners. The asymmetric geometry optimizes the usable sample volume while maintaining probe access.
Solution Approach 2:
The invention changes the dimensional configuration of the vial insert by introducing a non-circular cross-sectional shape. This dimensional change creates a geometry where the sample volume is optimized for probe penetration, allowing the capillary and electrode to access the sample effectively while minimizing wasted volume in corners or dead spaces that would exist in a circular cross-section.
2Quantity of substance
If the vial inner diameter is reduced to minimize sample volume, then less sample is required, but the capillary and electrode cannot simultaneously penetrate the sample without contacting the inner wall
Solution Approach 1:
The D-shaped or rectangular cross-section creates an asymmetric geometry where one side is flat or has a corner that can be positioned against the round vial wall. This asymmetry provides sufficient space on the opposite curved side for both the capillary and electrode to penetrate the sample simultaneously without contacting the inner wall, while still minimizing the overall sample volume required.
Solution Approach 2:
The vial insert geometry segments the sample space into accessible and inaccessible regions. The asymmetric shape creates defined zones where the sample is accessible to the probe while minimizing the volume of inaccessible sample, effectively segmenting the functional sample volume from the total sample volume.
3Quantity of substance
If conventional symmetric vial shapes are used, then manufacturing is simple, but the sample volume cannot be minimized while maintaining probe access
Solution Approach 1:
The vial insert employs an asymmetric D-shaped or rectangular cross-section instead of a conventional circular shape. This asymmetric geometry is specifically designed to minimize the sample volume required while ensuring that the capillary and electrode can simultaneously penetrate the sample without contacting the inner wall. The asymmetric shape creates optimal spacing between the probe elements and the vial wall.
Solution Approach 2:
The asymmetric cross-section creates different local geometries within the vial insert - the flat side or corner provides a reference surface for positioning against the round vial wall, while the curved side provides the sample access zone. This local differentiation of geometry optimizes both the minimum sample volume and the probe penetration capability in different regions of the vial.
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3(a)~3(c)
AI summary
Vials for reducing the volume of sample that must be contained within the vial when interfacing with a variety of analytical instruments are provided herein, and particularly, for use in analytical instruments that interact with a sample via a "polar" or asymmetric probe, including in capillary electrophoresis, liquid chromatography, and gas chromatography, by way of non-limiting example. In accordance with various aspects of the present teachings, the vials can reduce the waste of expensive and/or scarce samples common in the round vials and vial inserts conventionally used in the art.