The majority of chromatographers use reversed phase silica-based
HPLC columns due to their excellent retention characteristics,
high theoretical plate number, good cost-performance and ease of
use. C18 or ODS reversed phase
columns are the most general and popular types. Monomeric and
polymeric types are available differing considerably in their
retention characteristics.
Nacalai has been offering the monomeric type COSMOSIL 5C18-MS
and the polymeric type COSMOSIL 5C18-AR
columns, both well received by many chromatographers due to their
excellent performance. However, the COSMOSIL 5C18-AR-II
can be used for a wider range of compounds than other polymeric
types of columns already in use.
Material characteristics
COSMOSIL 5C18-
AR-II
Silica gel
high purity porous spherical silica
Average particle size
5µm
Average pore size
approx. 120Å
Specific surface area
approx. 300m2/g
Stationary phase
polymeric octadecyl group
End capping treatment
near-perfect treatment
Carbon content
approx. 17%
Characteristics
The COSMOSIL 5C18-AR-II packed
column features a polymeric and near-perfectly end capped type of
C18 reversed phase material that
employs an ultra-pure silica gel low in metal impurities. In
addition, it has stronger acid resistance than the COSMOSIL 5C18-AR.
The COSMOSIL 5C18-AR-II column
is especially effective for the separation of chelating compounds
as well as both acidic and basic compounds.
This series of columns is also highly recommended for a wide range
of applications particularly in situations where monomeric-type
column (for instance, COSMOSIL 5C18-MS-II)
is not as effective as expected.
Acid
resistance
The acid resistance of Cosmosil 5C18-AR-II
is much improved compared with 5C18-AR.
It retains high performance even in case of acidic mobile phase
used to separate proteins and peptides.
