Abstract
We developed a coupled dual column HPLC-system for on-line sample processing, trace enrichment and analysis of ribonucleosides and ribonucleotides. The fully automated HPLC-analyzer tolerates the direct and repetitive injection of biological fluids such as serum or urine by use of an unique bonded-phase precolumn material which allows the simultaneous performance of covalent affinity and size-exclusion chromatography.