Drug monitoring by high performance liquid chromatography using automatic sample preparation technique

The protein-coated ODS column (TSKprecolumn BSA-ODS) or chemically treated silica column (TSKprecolumn SW) was used for the enrichment of the drugs and the removal of proteins in plasma or serum. The enriched drugs in the precolumn are introduced automatically to the analytical column using the column switching device. Drugs such as theophylline or ethosuximide were analysed successively within 15 min including sample preparation. The drugs in plasma can be analysed with good recovery and good precision.