Chromolith® HPLC Columns

Separation Efficiency

Despite their capacity for high-throughput analysis, Chromolith® HPLC columns offer excellent separation efficiency and peak resolution. This is due to the high permeability and porosity of the columns' silica skeleton, which results in significantly lower back pressure and more flexible flow rates than conventional particulate columns. Furthermore, in contrast to particulate columns, column length is not pressure limited with Chromolith®.

For more complex separations it is still necessary to use long columns in order to provide the separation efficiency required for the resolution of all compounds of interest. To answer this need, a variety of Chromolith® column lengths are available for samples of different complexities. Moreover, Chromolith® HPLC columns can be connected in series, using the Chromolith® Column Coupler, to produce a column with a high plate count at low back pressure. In contrast, conventional particulate columns may not be lengthened, as this would cause excessive back pressure.

Separation Efficiency of Chromolith® vs. Particulate Columns

The van Deemter plot of the Chromolith® column clearly demonstrates that separation efficiency does not decrease significantly when the flow rate is increased, as is the case with conventional particulate columns. It is therefore possible to operate monolithic columns at high flow rates with minimal loss of peak resolution.

Even the traditional plate-count method of measuring quality shows that Chromolith® columns offer better separation efficiency than standard 5 μm particulate columns, and just as good as 3.5 μm columns, but with the ability to continue up to 9 mL/min without reaching HPLC system pressure limits.