>Pierceā„¢ Peptide Retention Time Calibration Mixture SSAAPPPPPRGISNEGQNASIKHVLTSIGEKDIPVPKPKIGDYAGIKTASEFDSAIAQDKSAAGAFGPELSRELGQSGVDTYLQTKGLILVGGYGTRGILFVGSGVSGGEEGARSFANQPLEVVYSKLTILEELRNGFILDGFPRELASGLSFPVGFKLSSEAPALFQFDLK