Reverse-phase separation and electrochemical detection of neuropeptides.

The reverse-phase separation of neuropeptides using isocratic conditions is described. Each component of the mobile phase was examined for its ability to influence the separation of complex mixtures of neuropeptides. Manipulation of buffer strength, pH, organic modifier and column type provided sufficient flexibility to resolve closely related neuropeptides. Amperometric detection of oxidizable amino acids in the peptide sequence of a number of endogenous neuropeptides proved suitable for the identification of peptide standards and quantification of neural lobe arginine vasopressin and striatal methionine enkephalin.