Purifying and Concentrating Imiquimod and Metabolites from Large Volumes of Urine

3M Bioanalytical's Empore ci8 47mm 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.

SDB-RPS is a poly(styrenedivinylbenzene) copolymer that has been modified with sulfonic acid groups to make it hydrophilic.  SDB-RPS is not bonded to silica but is a 100% copolymeric particle that is spherical, porous and cross-linked.  The sulfonation imparts unique selectivity for organic analytes that are polar in nature, such as drugs, drug metabolites, water-soluble pesticides and pesticide metabolites.  SDB-RPS is also useful for comprehensive drug screening, in which a wide range of analytes are simultaneously extracted.  SDB-RPS can be used as a reversed phase sorbent and substituted into existing methods.  Organic analytes with polar character have been shown to extract better on SDB-RPS than on traditional C18 bonded silica.