 Any glassware that is to come into contact with RNA should be pretreated with diethylpyrocarbonate (DEPC) and plastic materials should be disposable.One of the most common uses for molecular-weight size markers is in gel electrophoresis.The purpose of gel electrophoresis is to separate proteins by physical or chemical properties, which include charge, molecular size, and pH.< When separating based on size, the ideal method is SDS-PAGE or polyacrylamide gel electrophoresis and molecular-weight size markers are the appropriate standards to use.