Capillary zone electrophoresis of two synthetic neuropeptides: examination of detectability and resolution as a...

The capillary zone electrophoretic behavior of substance P and methionine enkephalin, when the amount of peptide was increased at a constant injection volume, was examined using a 50-microns I.D. capillary. Peak-shape distortion (asymmetry) increased when the concentration of these two peptides exceeded 1% of the buffer concentration. Increasing the buffer concentration increased the peak height and decreased the peak width, leading to higher detectability and resolution, respectively. Peak area versus analyte concentration remained linear, even under the overloading conditions that distorted the peak shape.