The Use of Bonded-Phase Extraction Columns for Rapid Sample Preparation of Benzodiazepines and Metabolites from Serum for HPLC Analysis

A simple, rapid method for the determination of the benzodiazepines, diazepam and chlordiazepoxide, and their metabolites by high performance liquid chromatography (HPLC) has been developed. The procedure is applicable to the assay of other similar drugs in biological fluids. The method utilizes BondElut extraction columns to facilitate the extraction. BondElut columns selectively adsorb the benzodiazepines and metabolites from serum at a pH of 9.0. The compounds are eluted with 300 microliters of methanol which makes sample concentration rapid, if even necessary. Analysis is performed using isocratic reversed-phase chromatography, and quantitation is carried out by ultraviolet (UV) detection. Using this procedure, it is possible to determine drug and metabolite levels to as low as 25 ng/ml in 0.5 ml of serum.