Use of reduced sorbent bed and disk membrane solid-phase extraction for the analysis of pharmaceutical compounds in biological fluids, with applications in the 96-well format

Significant improvements in the isolation of pharmaceutical compounds from plasma, serum and urine, have been achieved using ultra low mass sorbent bed and thin disk solid-phase extraction (SPE) material. The use of low sorbent masses or disk SPE material has allowed a significant reduction in solvent usage and extraction times. The reduction in solvent volumes required has allowed elution volumes to be reduced to as low as 30 mu l with high and consistent analyte recovery. Several SPE RP-HPLC methods have been developed using these materials, including LC-MS methods. When the chromatographic conditions allow the eluent to be injected directly or injected after dilution with distilled water Empore disks are the extraction media of choice due to the materials low elution volume requirements. When operated in the 96-well microtitre format this micro-extraction provides a very efficient throughput and requires little sample manipulation.