Optimizing design and employing permeability differences to achieve flow confinement in devices for spatial multidimensional liquid chromatography.

In spatial multi-dimensional liquid chromatography (LC) devices the flow of each dimension has to remain in the corresponding region, otherwise the separation efficiency is undermined. Adequate flow-confinement measures are necessary. Here, the use of permeability differences across different compartments of spatial two-dimensional (2D) and three-dimensional (3D) LC devices as a method to guide fluid flow and reduce analyte loss during the first, second- and third-dimension development was investigated with computational fluid dynamics (CFD) simulations. In case of 2DLC devices, it was shown that porous barriers with a permeability on the order of 10 ^-12 m ² suffice to keep the total sample spillage from an open ¹ D channel under 1%. In case of 3DLC devices, it was shown that flow confinement could be achieved using an open ¹ D channel in combination with a highly-permeable monolith (permeability on the order of 10 ^-12 m ² ) in the second-dimension ( ² D) and a less permeable packing with a permeability on the order of 10 ^-15 m ² (e.g. 1 μm particles) in the third-dimension ( ³ D). Additionally, the impact of the ³ D flow-distributor has been studied and a novel design, capable of limiting the spillage to the other dimensions to the absolute minimum, is proposed.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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