SDS (Sodium Dodecyl Sulfate)

What is Sodium Dodecyl Sulfate?

Sodium Dodecyl Sulfate (SDS), also known as sodium lauryl sulfate, is a synthetic anionic detergent with the chemical formula C₁₂H₂₅NaO₄S. It is widely used in laboratory settings for its ability to disrupt non-covalent interactions in proteins, leading to denaturation and uniform negative charge coating. This property makes it essential in SDS-PAGE (Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis), where proteins are separated primarily by molecular weight rather than charge.

How does SDS function in protein analysis?

In SDS-PAGE, SDS binds to proteins in a ratio of approximately one molecule per two amino acids, imparting a strong negative charge that overwhelms the protein's intrinsic charge. This ensures that separation during electrophoresis is based on size alone. The addition of reducing agents like DTT or TCEP further breaks disulfide bonds, ensuring complete denaturation. SDS is also used in cell lysis buffers and in the preparation of protein samples for mass spectrometry and other analytical techniques.

What are the safety and handling considerations for SDS?

SDS is classified as a skin and eye irritant under GHS and is regulated under REACH and TSCA. It can cause irritation upon prolonged exposure and should be handled with appropriate personal protective equipment (PPE). SDS is not considered highly toxic but can be harmful if ingested or inhaled in large quantities. Proper disposal in accordance with local regulations is required. SDS is also used in consumer products such as shampoos and detergents, but laboratory-grade SDS must meet high purity standards (e.g., ACS or USP grade).

Related concepts

SDS is frequently used alongside other reagents such as Tris, HEPES, and β-mercaptoethanol in sample preparation. It is also integral to the analysis of protein purity and integrity via SDS-PAGE, often combined with CoA and SDS-PAGE gels for quality control in biopharmaceutical manufacturing.