It is well known that in flash chromatography, the shape and size of the silica material, irregular or spherical, large or small particles, affects the amount of material that can be purified on a flash column. The smaller, more spherical particles and the higher the surface area, the more material can be separated. In this application note, we compare the amount of a threecomponent mixture that can be separated on 25 g columns with different silica material, namely Biotage® SNAP KP-Sil (average 50 µm irregular particles), Biotage® Sfär Silica (60 µm spherical particles) and Biotage® Sfär Silica HC (20 µm spherical particles) on a Biotage® Selekt flash purification instrument.
A 10 g sample of three similar compounds, dimethyl phthalate, diethyl phthalate and dibutyl phthalate (Figure 1) was separated on three different 25 g columns:
» Biotage® SNAP KP-Sil
» Biotage® Sfär Silica D
» Biotage® Sfär Silica HC D
Chromatography was done using a Biotage® Selekt instrument and the chromatograms were compared.
The criterion for separation used was to obtain separation between peak 2 and peak 3 using a threshold set at 100 mAU at 254 nm on the Biotage® Selekt.