Ontwsep™ Florisil SPE CartridgesOntwsep Florisil is a standard solid phase extraction sorbent that produces good results at a low cost. Florisil adsorbent is primarily composed of three components: silicon dioxide (84%), magnesium oxide (15. 5%), and sodium sulphate (0. 5%). It is effective for adsorbing polar chemicals from non polar matrices, such as organochlorine pesticide residues, amines, and organic acids.