The present paper reports on the separation of a mixture of fluorescein isothiocyanate-labeled angiotensin I and II peptides in a shear-driven nanochannel with a C-18-coating and using an eluent consisting of 5% acetonitrile in 0.02 M aqueous phosphate buffer at pH 6.5. The flat-rectangular nanochannel in fused silica consisted of an etched structure in combination with a flat moving wall. The very fast separation kinetics that can be achieved in a nanochannel allowed to separate the angiotensin peptides in less then 0.2 s in a distance of only 1.8 mm. Plate heights as small as 0.4 mu m were calculated after substraction of the injection effect. (c) 2006 Elsevier B.V. All rights reserved.