KS-V Peptide is obtained by calculating the purity of the peptide by measuring the ultraviolet absorption value of the peptide bond in the target at a specific absorption wavelength by reversed-phase high-performance liquid chromatography (RP-HPLC), and is separated and purified by gradient elution with water and acetonitrile . Among them, moisture and residual salt cannot be measured by UV detector, and there are other impurities in the test results, including incomplete sequence peptides (short peptides with one or more amino acid residues less than the target peptide), truncated sequences due to preventing Generation of incomplete sequence peptides (polypeptides produced by capping), incompletely deprotected peptides (polypeptides produced during synthesis or final cleavage).