Sapphire Prestained Protein Standard 10-180kDa contains approximately 0.1-0.5 mg/ml of each protein in the buffer (20 mM Tris-phosphate, pH 7.5 at 25°C), 2 % SDS, 0.2 mM Dithiothreitol, 3.6 M Urea, and 15 % (v/v) Glycerol). Sapphire Prestained Protein Standard 10-180kDa is a blue protein standard with 11 pre-stained proteins covering a wide range molecular weights from 10 to180 kDa. Proteins are covalently coupled with a blue chromophore, and two reference bands (at 25 kDa and 72 kDa respectively) are enhanced in intensity when separated on SDS-PAGE (Tris-glycine buffer). Sapphire Prestained Protein Standard 10-180kDa is designed for monitoring protein separation during SDS-polyacrylamide gel electrophoresis, verification of Western blot transfer efficiency on membranes (PVDF, nylon, or nitrocellulose) and for approximating the size of proteins.