Fabrication of monolithic frits and columns for chip‐based multidimensional separation devices.

In this work, devices for two‐dimensional separations are considered. The device contains a flow distributor, a first‐dimension channel, and 17 second‐dimension outlets. In the design, all connections between the first‐dimension channel, the flow distributor, and the second‐dimension outlets were tapered, with a minimal diameter of 20 μm. The use of photo‐masking is explored for the fabrication of monolithic frits in all tapered connections. Monolithic frits with optimized permeability and length were successfully fabricated in all 33 tapered channels through light‐induced polymerization, photo‐masking, and selective exposure. The efficacy of the monolithic frits was demonstrated by creating a packed bed of 15‐μm particles, confined within the first‐dimension channel. The outlet of the first‐dimension channel was successfully connected to a mass spectrometer. Effective flow confinement was demonstrated with a reversed‐phase separation of a mixture of five standard peptides. [ABSTRACT FROM AUTHOR]