Automated Determination of Drugs in Serum by Liquid Chromatography with Column-Switching.

This is a fully automated system for determining six common antiepileptic drugs and two principal metabolites of carba-mazepine in serum. it is based on “high-performance ” liquid chromatography (HPLC), with column switching. TSKpreco-lumn BSA-ODS and TSKgel 005-1 20A (both from Toyo Soda) were used as the precolumn and analytical column, respectively. The former contains octadecylsilyl resins treat-ed with bovine serum albumin (BSA), and does not adsorb macromolecules such as serum proteins but retains small lipophilic molecules such as antiepileptic drugs. Serum sam-ples are directly injected onto the precolumn. After washing out the serum proteins from the precoiumn with sodium phosphate buffer, we switch the column connections to introduce the retained substances onto the analytical column and elute with a step-gradient of acetonitrile/sodium phos