J.Heřt

-synonyms: solid core particles, Fused-core particles -Most recent available particle size is 1.7  m (core 1.25  m, layer 0.23  m) [2] [1]

Vendors and Available phases VendorColumn/product name Average particle diameter (μm) Shell thickness (μm)Stationary phase chemistry Advanced Material Technology Halo C18, C8, HILIC, RP-amide, phenylhexyl, pentafluorophenyl Advanced Material Technology Halo Peptide-ES 160 Å C18 AgilentPoroshell C18, C8, C3 AgilentPoroshell EC-C18, SB-C18 Sigma–AldrichAscentis Express C18, C8, HILIC, RP-amide, phenylhexyl, pentafluorophenyl Sigma–Aldrich Ascentis Express Peptide-ES 160 Å C18 PhenomenexKinetex C18, XB-C18, C8, HILIC, pentafluorophenyl Macherey-NagelNucleoshell2.70.5RP-18, HILIC Thermo ScientificAccucore C18, aQ, RP-MS, HILIC, phenylhexyl, pentafluorophenyl SunniestSunShell2.60.5C18 Commercially not available Eiroshell C18 [5]

History of LC particles size -1960s – The concept of shell particles was first applied by Horvath and co-workers, leading to the start of HPLC [9] - Kirkland proposed better efficiency of 30 – 40  m core-shell particles compared with fully-porous particles [9] -1970s - first Core-shell particles were developed – improvement in the manufacturing of high-quality fully porous particles inhibit success of the shell particles [9] - 10  m porous particles -1980s - 5  m porous particles -1990s - 3  m porous particles -Present – sub-2  m porous particles and Core shell

Sub-2  m particles limitation -High mobile phase velocity obtained with high pressure gradient generates FRICTIONAL HEAT[3] -is increasing with increasing flow rate -is causing a serious degrease of column efficiency Core shell - higher efficiency with sub-2  m particles [3]

Van Deemter equation: H = A +B/u + Cu A-value (Eddy dispersion) - narrow particle size distribution in addition to an enhanced roughness of their surface compared to porous particles, leading to a smaller A-coefficient by about 40%[4, 3] Core shell columns and Van Deemter [6] [8]

B-value (Longitudinal diffusion) - the solid core also has a direct consequence on the B-value because analytes cannot axially diffuse in the solid inner core; 20% decrease in comparison with porous particles [4, 3] C-value (Mass transfer resistances) – solid core, impenetrable by analytes cause shorter diffusion path – C-value is reduced [4, 3] Core shell columns and Van Deemter [2] [1]

Core shell columns and Van Deemter [6]

Core shell columns and Van Deemter [7]

Core shell columns and Van Deemter [8]

Applications – Fast HPLC [10]

Applications – UPLC efficiency in HPLC [10]

Applications – Comparable to sub-2  m columns [10]

Fig. 4. Zoomed chromatograms of BSA. Columns: (1) Aeris WIDEPORE C18 (150 mm × 2.1 mm), (2) Acquity BEH300 C18 (150 mm × 2.1 mm), and (3) Ascentis Express Peptide ES C18 (150 mm × 2.1 mm). Temperature: 50 °C, injected volume: 1 μL, detection: 210 nm. Mobile phase A: 0.1% TFA in water, mobile phase B: 0.1% TFA in acetonitrile. Gradient steepness: β = 4%ΔB/min. Applications – Better efficiency [11]

Core-shell Advantage -Fast HPLC – shorter diffusion path -Unusual efficiency in HPLC -Efficiency comparable to sub-2  m particle, but with about one-half pressure drop -Better efficiency at high mobile phase velocities -Sharp Peaks – narrow particle size, consistent bed -Lower mobile phase comsuption -Posibility of next miniaturisation of particles in LC

[1] [2] [3] Gritti, F., Guiochon, G. Comparison of heat friction effects in narrow-bore columns packed with core–shell and totally porous particles, Chemical Engineering Science 65(2010) [4] Ruta, J. et col. Evaluation of columns packed with shell particles with compounds of pharmaceutical interest, Journal of Chromatography A 1228 (2012) [5]Fekete. S et. col. Fast liquid chromatography: The domination of core–shell and very fine particles, Journal of Chromatography A 1228(2012)57-71 [6] Gritti, F., Guiochon, G. Mass transfer kinetics, band broadening and column efficiency, Journal of Chromatography A 1221 (2012) 2-40 [7] [8] Oláh E., Fekete S. et col. Comparative study of new type, sub-2  m fully porous and monolith stationary phases, focusing on mass-transfer resistance [9[ Fekete S. et col. New trends in reversed-phase liquid chromatographic separations of therapeutic peptides and proteins: Theory and applications, Journal of Pharmaceutical and Biomedical Analysis, In-press [10] [11]Fekete. S et. col. Evaluation of a new wide pore core-shell material (Aeris TM WIDEPORE) and comparoson with other existing stationary phases for analysis of intact proteins, Journal of Chromatography A 1236(2012) Literature