4 types of traditional SPE de absorbents for most of commonly used applications in column of 3 or 6 ml and luer connection.C18: End-capped silica-based octadecyl. Suitable for non-polar compounds. Surface area 300 m2/g, particle size 40-60 µm, pore size 120 Å.SILICA: Silica unbounded silica gel. Suitable for polar compounds. Surface area 480 m2/g, particle size 40-75 µm, pore size 70 Å.FLORISIL: Florisil pesticide grade. Suitable for halogenated and polar compounds such as multiresidual pesticides. Particle size 150-250 µm.NH2: Silica-based aminopropyl. Suitable for moderately polar and acidic compounds. Surface area 200 m2/g, particle size 40-75 µm, pore size 100 Å