Supercritical Fluid Chromatography Column Segmentation
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Solution Overview
Problem
Chromatographic separation efficiency in CO2-based and supercritical fluid chromatography is hindered by cooling-induced changes in the mobile phase, leading to heterogeneity and reduced separation efficiency due to axial expansion and heat loss along the chromatography column.
Innovation Solution
The use of multiple non-contiguous separating segments with interposed heating segments to maintain a homogeneous mobile phase by replacing heat lost during axial expansion, allowing for optimized separation conditions and consistent physical properties of the mobile phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a single long chromatography column is used for sample separation, then the separation path length is increased, but the mobile phase experiences axial expansion and cooling leading to heterogeneity and reduced separation efficiency
Solution Approach 1:
The single long chromatography column is divided into multiple shorter column segments. Between these segments, heating zones are introduced to reheat the mobile phase, compensating for cooling effects from axial expansion. This segmentation allows the mobile phase to maintain its supercritical state and homogeneity throughout the separation process while still achieving sufficient separation path length through the series of segments.
2Loss of energy
If the mobile phase is allowed to cool during axial expansion, then energy loss is reduced, but temperature heterogeneity develops leading to peak distortion and reduced separation efficiency
Solution Approach 1:
The temperature parameter of the mobile phase is actively controlled by introducing heating zones between column segments. These heating zones restore the temperature of the mobile phase that has cooled during axial expansion through the previous segment, maintaining consistent thermal conditions for optimal separation and preventing peak distortion.
3Stability of the object's composition
If heating is applied to maintain mobile phase temperature, then mobile phase homogeneity is improved, but device complexity increases due to additional heating segments
Solution Approach 1:
The heating zones are integrated into the chromatography system architecture by positioning them between column segments, combining the separation function of the columns with the temperature control function of the heating zones. This merging approach maintains mobile phase homogeneity without requiring separate, independent heating systems, thereby limiting the increase in device complexity.
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 approach results in improved separation efficiency, reduced peak distortion, and increased consistency across runs by maintaining a homogenous mobile phase, enabling more reliable and robust sample separation.
Implementation Method 1
heating segments to maintain a homogeneous mobile phase by replacing heat lost during axial expansion
Implementation Method 2
as the supercritical fluid (or a near supercritical fluid) moves down the length of a chromatography column or separating segment, it expands. Correspondingly, as the supercritical mobile phase expands, it also cools.
Data Source
AI summary
The present technology uses one or more separating segments, i.e. chromatography columns, aligned in series along a flow path. The separating segments are divided by a plurality of heating elements or are heated directly. The heating elements heat the supercritical mobile phase and sample to replace heat lost due to axial expansion of the mobile phase along the mobile phase flow path.