Determination of Caffeine in Human Urine Samples Free of the Interference of its Metabolites by Reversed-Phase Liquid Chromatography Using Solid-Phase Extraction from Sample Clean-Up

摘要

This study describes a rapid assay for caffeine in urine samples combining solid-phase extraction techniques for sample clean-up, and conventional reversed-phase conditions for elution. The samples are previously conditioned usin24Jul1992g C18 solid-phase extraction columns, and chromatographed on an HP-Hypersil ODS-C18 column with a mobile Phase consisting of acetoni tr i le-phosphate buffer (pH=3) in gradient elution mode. The detection is set at 275 nm. These conditions provide a complete resolution of caffrence in c. a. 6 min. The described system can oe applied to the simultaneous determination of caffeine and its main metabolites. The selectivity, sensitivit and precision at therapeutic levels make it suitable for caffeine monitoring.