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In a paper published in the journal Separation Sciences, analytical chemists Noor Abdulhussain, Suhas Nawada and Peter Schoenmakers of the Van 't Hoff Institute for Molecular Sciences present the fabrication and use of polymeric monoliths, both as frits and columns, in two dimensions of a three-dimensional spatial separation device.

Photo: HIMS

When using devices intended for multi-dimensional separations, controlling the boundaries between the different separation dimensions is critical. This is particularly relevant for maintaining clear definitions of the different stationary phases for each dimension. Using photo-masking and selective polymerization, the researchers were able to fabricate retaining frits on each side of the first-dimension separation channel. As a result, the packed bed of 15-micrometre particles in the first-dimension channel is maintained, enabling the separation of a standard peptide mix.


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 minimum 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.

Publication details

Noor Abdulhussain. Suhas H. Nawada, Sinéad A. Currivan, Peter J. Schoenmakers: Fabrication of monolithic frits and columns for chip-based multidimensional separation devices. Journal of Separation Science, first published 23 January 2022. DOI: 10.1002/jssc.202100901