Analysis of neuropeptides by perfusion liquid chromatography/electrospray ion-trap mass spectrometry.

Perfusion high-performance liquid chromatography (HPLC) combined with electrospray ion trap mass spectrometry (ITMS) was evaluated for the determination of neuropeptides in plasma. Perfusion HPLC offers the capability of resolving neuropeptides spiked into plasma in 5 min compared to the 30-60 min separations performed on packed capillary C18 columns. Electrospray combined with the ITMS provides the ability to ionize these neuropeptides and mass analyze them with high sensitivity and specificity. Sub-picomole quantities of neuropeptides injected on-column could be specifically detected in a plasma matrix. The electrospray-ITMS mass spectrum of each neuropeptide showed multiply charged ions which could be used to determine or confirm their molecular weights.