The efficiency of several reversed-phase columns for the purity evaluation of human growth hormone (hGH) was investigated.Samples of partially deamidated hGH were analyzed with several reversed-phase high-performance liquid chromatog. (RP-HPLC) columns, i.e., three kinds of Bu (C4) columns and two alkali-resistant Octadacyl (C18) columns.Using the eluent at pH 7.5, good resolution (Rs) (Rs>1.0) between the hGH peak (main peak) and the deamidated hGH peak (desamido peak) was obtained with most of the C4 columns, but better resolution was observed with the Develosil ODS-UG-5 column (Rs=1.50).For the two alkali-resistant columns, Develosil ODS-UG-5 and Asahipak ODP-50, the resolution was also measured under an alk. condition (pH 8.5).The resolution at pH 8.5 was greatly superior to that at pH 7.5.
