USE OF REDUCED SORBENT BED AND DISK MEMBRANE SOLID-PHASE EXTRACTION FOR THE ANALYSIS OF PHARMACEUTICAL COMPOUNDS IN BIOLOGICAL-FLUIDS, WITHAPPLICATIONS 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 u se of low sorbent masses or disk SPE material has allowed a significan t reduction in solvent usage and extraction times. The reduction in so lvent 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 l ow elution volume requirements. When operated in the 96-well microtitr e format this micro-extraction provides a very efficient throughput an d requires little sample manipulation.