NUCLEOSHELL phases

NUCLEOSHELL® core-shell silica phases for HPLC
Features

NUCLEOSHELL®

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

Lower back pressure also allows use on conventional LC systems

Pressure stability up to 600 bar

NUCLEODUR®

Summary of available NUCLEOSHELL® phases
Phase	Modification	% C	pH range	Particle size [µm]	USP	Structure
RP 18	Octadecyl, multi-endcapping	7.5	1–11	2.7	L1
PFP	Pentafluorophenyl, multi-endcapping	~ 3	1–9	2.7	L43
HILIC	Ammonium – sulfonic acid	1.3	2–8.5	2.7	–

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
Eluent: Flow rate: Temperature: Detection:	acetonitrile – water (60:40, v/v) 1 mL/min 25 °C UV, 254 nm
Peaks: 1. Naphthalene 2. Ethylbenzene	Better resolution at lower back pressure and shorter retention time