The Milli-SPE family of solid phase extraction (SPE) cartridges features 3M Empore extraction disk membranes, which produce clean extracts and minimize particle fines to potentially extend LC/MS/MS column life and reduce instrument downtime. The cartridges are available in a selection of sorbentsC2, C8 and C18; Universal Resin; and Mixed Phase Cation resin. Low elution volumes result in higher analyte concentrations and increased sensitivity. The membranes also eliminate channeling and reduce the risk of analyte loss, which can occur with other packed particle bed SPE devices, while maintaining fast sample flow rates when processing biological fluids. For isolating and concentrating analytes at low detection levels, the SPE method eliminates the interferences that contribute to signal suppression. SPE yields clean, concentrated analyte solutions that improve signal-to-noise ratios and lower limits of quantitation in LC/MS/MS analysis.