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What type of chromatography is SDS-PAGE used for?

  1. Separation based on charge

  2. Separation based on size

  3. Separation based on mass

  4. Separation based on polarity

The correct answer is: Separation based on mass

SDS-PAGE, which stands for Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis, is a technique primarily used for separating proteins based on their mass. The key component of this method is sodium dodecyl sulfate (SDS), an anionic detergent that denatures proteins and coats them with a negative charge. This uniform negative charge allows proteins to migrate through a polyacrylamide gel when an electric field is applied. The size of the proteins plays a crucial role during the separation process; smaller proteins can move faster through the gel matrix, while larger proteins encounter more resistance and move more slowly. Thus, the separation achieved in SDS-PAGE is specifically based on the molecular weight of the proteins, enabling researchers to analyze and compare the sizes of different proteins effectively. While other types of chromatography, such as ion exchange chromatography or size exclusion chromatography, might separate based on charge or size, respectively, SDS-PAGE distinctly focuses on mass as the primary factor for separation.