Determination of an opiate pentapeptide by on-line reversed phase preconcentration and ligand exchange chromatography with spectrofluorometric detection

Abstract

In order to study the occurrence of the opiate pentapeptide β-[D-Ala2,4, Tyr5] CM-5-NH2 in the 10−9–10−5 M concentration range, we have developed a new method consisting of extraction of the peptide from its buffered aqueous medium onto a reversed phase cartridge of 50 μL void volume, followed by on-line injection onto a Cu(II) modified silica gel column. The acetonitrile-rich mobile phase allows detection of the natural fluorescence of the peptide at the picomole level.