Ontwsep™ Carb/NH₂ is made of equal parts Carb (graphitised carbon black, upper layer) and NH₂ (amino group, lower layer), separated by a polyethylene filter plate. Graphitised carbon black.

 After surface treatment, it has a strong adsorption capacity for planar molecular structures, such as chlorophyll and carotene in fruits and vegetables. NH₂ is aminopropyl bonded silica gel, which is used to remove interfering substances such as fatty acids and organic acids. This solid phase extraction cartridge is widely used in detecting pesticide residues in food.