3M bioanalytical's Empore c18 90 Disk-
Commonly used for the solid phase extraction of analytes from complex sample matrices. A variety of functional groups, such as octadecyl (C18) and octyl (C8) can be bonded to the silica surface to provide non polar interactions. Each of these sorbents exhibits unique properties of retention and selectivity for a particular analyte. The choice of which sorbent is best for a particular method will be influenced by the percent recovery of analyte from the sample matrix and the cleanliness of the resulting chromatography.