The Mystery of Sodium Dodecyl and Laureth Sulfates

Every morning we wake up and the first thing that we do is brush our teeth. But have you ever wondered what do the tube of toothpaste and the bar of soap that we use contain? Well they contain a substance called as SDS. Let us find out more about this substance.

SDS is on your hands and in your mouth too! You wake up every morning and brush your teeth. But have you ever wondered what your toothpaste or a bar of soap contains? Well, they contain a substance known as SDS.

What is SDS?
Sodium dodecyl sulphate (SDS), also known as sodium lauryl sulphate (SLS), is a
substance found in toothpaste, liquid soaps and detergents and is used for different protein studies in Biochemistry. In its purified state, SDS is a white powder of medium molecular weight (M.W. or F.W. of 288.38, C12H25O4SNa). A modified form of SDS is sodium laureth sulphate (M.W. or F.W. 418.53, C12+2nH25+4nNaO4+nS). Both these compounds have a lot of scientific and household uses.

In the Lab
SDS is used during the protein purification process and is used for studying the
protein molecular weights by a technique called polyacrylamide electrophoresis (PAGE). Proteins are dissolved in a solution of SDS, which is an anionic detergent that binds one SDS molecule to every two amino acid residues in the entire protein molecule.

Sodium dodecyl sulphate (the CAS number is 151-21-3) is a detergent that promotes a linear or a straightened, non-globular configuration of the native proteins. Cross-linking disulfide covalent bonds in the protein are broken by the use of mercaptoethanol (2-thioethanol) or dithiothreitol. These chemical treatments permit different types of proteins, which are characterized and defined according to their specific molecular weight.

In the Home
SDS plays an important role in homes as they have foaming characteristics that are used
in toothpastes, liquid hand soaps and liquid detergents.

Toothpastes commonly contain SDS that helps separate, free and remove food and debris in and around the teeth and gums helping prevent tooth decay and pyorrhea of the gums. Hand washes, liquid soaps and some laundry detergents use SDS to remove dirt and debris.