title: Evaluation of 5 µm Superficially Porous Particles for Capillary and Microfluidic LC Columns.
abstract: Large-size (4-5 µm) superficially porous particles yield lower plate heights (e.g., the minimal reduced plate height orhmin≈ 1.5) than fully porous particles of a similar size when packed into large-bore columns. This property allows for better chromatographic performance without the higher pressures required for smaller particles. This study explores the use of such particles in microfluidic LC columns where materials and fitting pressure limits can constrain the size of particle used. The theoretically predicted performance improvements compared to fully porous particles were not demonstrated in capillary columns (withhmin≈ 2 for both particle types), in agreement with previous studies that examined smaller superficially porous particles. Microfluidic columns were then compared to capillary columns. Capillary columns significantly outperformed microfluidic columns due to imperfections imposed by microfluidic channel asymmetry and world-to-chip connection at the optimal flow rate; however, superficially porous particles packed in microfluidic LC columns had flatter plate height versus flow rate curves indicating potential for better performance at high reduced velocities.
authors.affiliation: Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: James P
authors.initials: JP
authors.lastname: Grinias
authors.affiliation: Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA ; Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Kennedy
keywords: capillary LC; chip-LC; core-shell; liquid chromatography; microfluidics; superficially porous particles