High-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve

Silicalite is a molecular sieve that contains an intricate system of channels approximately 6 Angstrom in diameter. These channels an hydrophobic and have been shown to retain relatively small hydrophobic and hydrophilic molecules from aqueous and biological samples. Silicalite is shown to be a restricted-access medium that permits the injection of biological fluids directly onto a HPLC column packed with Silicalite, eliminating the need for sample preparation. The sample macromolecules elute with high recovery mostly at the extraparticulate void. Simultaneously, Silicalite allows various drugs and metabolites to enter the channels and be retained. Recoveries >90% were generally obtained for a wide variety of drugs and their metabolites from human serum and urine. (C) 1998 Elsevier Science B.V.