QUANTITATIVE-DETERMINATION OF POLYPEPTIDES BY GRADIENT ELUTION HIGH-PRESSURE LIQUID-CHROMATOGRAPHY

High pressure liquid chromatographic (HPLC) methods are described for the quantitative determination of polypeptides in pharmaceutical dosage forms or in synthetic and natural products. Owing to the addition of an electrolyte for the inactivation of the residual silanol groups present on the modified silica surface, hydrophobic stationary phases were found which proved to be very suitable for the analyses of polypeptides. Excellent results were obtained with tetramethylammonium containing buffer systems at pH 3 in a gradient of water-methanol. Thus the polypeptides arginine-, lysine vasopressin, oxytocin, ACTH (1–24), ACTH, 3-endorphin, glucagon and porcine- and bovine insulin could be determined with coefficients of variation below 2%. Copyright © 1979 by Marcel Dekker, Inc.