Reversed-phase high-performance liquid chromatographic-radioreceptor assay of human cerebrospinal fluid neuropeptides. Maximizing recovery of picomoles of peptides and minimizing memory.

Reversed-phase high-performance liquid chromatography (RP-HPLC) is used to analyze neuropeptides in human cerebrospinal fluid (CSF) obtained from patients suffering from lower-back pain. Because CSF contains only femtomole to picomole amounts of those peptides, it is important to minimize any sample memory effect, while maximizing peptide recovery and avoiding any potential artifactual peak formation during chromatography. This study describes the phenomenon of active site occupancy by peptides on the RP-HPLC column, which is crucial when studying CSF where femtomole to picomole amounts of neuropeptides could be lost. Knowledge of those basic chromatographic factors is important whenever biologic extracts of peptides are applied to and eluted from an RP-HPLC column and then detected off-line with a radioreceptor assay, which is sensitive at the picomole level.