NUCLEOSHELL® core-shell silica phases for HPLC  

Core-shell technology:
Solid core of silicon dioxide,
homogeneous shell of porous silica
Highest efficiency compared to traditional totally porous materials
Pore size 90 Å; particle size 2.7 µm (core 1.7 µm); specific surface 130 m2/g;
RP 18 and RP 18plus phases are also available with particle size 5 µm (core 3.8 µm); specific surface 90 m2/g → Lower back pressure also allows use on conventional LC systems
Pressure stability up to 600 bar


Summary of available NUCLEOSHELL® phases
Phase Modification % C Particle size [µm] pH range USP Structure
RP 18 Octadecyl, multi-endcapping 7.8 2.7 1–11 L1
6.1 5
RP 18plus Octadecyl (monomeric),
5.7 2.7
2–9 L1
4.4 5
Bluebird RP 18 Octadecyl with polar endcapping 5 2.7 1–8 L1
Phenyl-Hexyl Phenyl-Hexyl, multi-endcapping 4.5 2.7 1–10 L11
PFP Pentafluorophenyl, multi-endcapping ~ 3 2.7 1–9 L43
HILIC Ammonium – sulfonic acid 1.3 2.7 2–8.5

Demands on HPLC separations are constantly increasing with respect to separation efficiency and detection limits as well as concerning the time requirements for each analysis. Core-shell technology sets new standards for increasing efficiency in research and quality control.

Benefits of core-shell technology Core-shell particles vs.
totally porous silica gel
Short diffusion paths
Rapid mass transfer (C term of the Van Deemter equation)
High flow velocity without peak broadening for fast LC
Narrow particle size distribution (d90/d10 ~ 1.1)
Stable packing
High heat transfer
Minimized influence of frictional heat
Column efficiency of NUCLEOSHELL® ~ 250000/m (HETP ~ 4 µm)

Resolution Rs as function of particle size
Columns: 50 x 4 mm
NUCLEOSHELL® RP 18, 2.7 µm
NUCLEODUR® C18 Gravity, 3 µm
NUCLEODUR® C18 Gravity, 1.8 µm
Flow rate:
acetonitrile – water (60:40, v/v)
1 mL/min
25 °C
UV, 254 nm
1. Naphthalene
2. Ethylbenzene
Better resolution at
lower back pressure and
shorter retention time

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