The 2mm I.D. semi-microbore columns of C18
phases are available in the COSMOSIL series. Compared with 4.6mm
I.D. columns, the semi-microbore columns are 5 times more
sensitive and reduce the solvent consumption by 80%.
The COSMOSIL semi-microbore columns perform best when used with
micro analysis HPLC equipment including tubing, injector and
The semi-microbore columns can replace existing COSMOSIL
analytical columns. Available packing materials are C18-MS,
C18-AR-II and C18-AR-300.
Please consult the table and the applications below for selection
high purity spherical porous silica
Average particle size
Average pore size
Specific surface area
End capping treatment
Sample load capacity
Sample load capacity is proportional to the cross section of the
column. Since the cross section of a 2mmI.D. column is about 1/5
that of a 4.6mmI.D. column: the optimum sample load is 1/5 that of
the analytical column.
In the example for naphthalene separation below, the theoretical
plate number of a 4.6mmI.D. column starts decreasing at 10µg of
the sample load; for the 2mmI.D. column the decreasing point is 2µg.
Dead volume greatly affects the semi-microbore column
performance.Use of a micro injector is highly recommended. In
order to avoid peak broadening, the injection volume should be
less then 1.0µl.
Recommended operating procedures
1.Flow rate must be less than 0.2 ml/min.
2.Pressure must be less than 15.0MPa
3.Filter solvents and samples with 0.5µm filters.
4.When you use a conventional HPLC system,the theoretical plate
number may be lowered by about 30%
5.Use of micro analysis HPLC equipment including tubing,injector
and detector cell is highly recommended.
Comparison with 4.6mml.D. column
The COSMOSIL semi-microbore columns are taking over the high
performance of COSMOSIL series.
The semi-microbore columns can be used in the same applications of
other analytical COSMOSIL columns.