Sodium dodecyl sulfate

Sodium dodecyl sulfate (SDS), synonymously, sodium lauryl sulfate (SLS), or sodium laurilsulfate, is a synthetic organic compound with the formula CH3(CH2)11SO4Na. It is an anionic surfactant used in many cleaning and hygiene products. The sodium salt is of an organosulfate class of organics. It consists of a 12-carbon tail attached to a sulfate group, that is, it is the sodium salt of dodecyl hydrogen sulfate, the ester of dodecyl alcohol and sulfuric acid. Its hydrocarbon tail combined with a polar 'headgroup' give the compound amphiphilic properties and so make it useful as a detergent. Also derived as a component of mixtures produced from inexpensive coconut and palm oils, SDS is a common component of many domestic cleaning, personal hygiene and cosmetic, pharmaceutical, and food products, as well as of industrial and commercial cleaning and product formulations. Sodium dodecyl sulfate (SDS), synonymously, sodium lauryl sulfate (SLS), or sodium laurilsulfate, is a synthetic organic compound with the formula CH3(CH2)11SO4Na. It is an anionic surfactant used in many cleaning and hygiene products. The sodium salt is of an organosulfate class of organics. It consists of a 12-carbon tail attached to a sulfate group, that is, it is the sodium salt of dodecyl hydrogen sulfate, the ester of dodecyl alcohol and sulfuric acid. Its hydrocarbon tail combined with a polar 'headgroup' give the compound amphiphilic properties and so make it useful as a detergent. Also derived as a component of mixtures produced from inexpensive coconut and palm oils, SDS is a common component of many domestic cleaning, personal hygiene and cosmetic, pharmaceutical, and food products, as well as of industrial and commercial cleaning and product formulations. SDS is in the family of organosulfate compounds, and has the formula, CH3(CH2)11SO4Na. It consists of a 12-carbon tail attached to a sulfate group, that is, it is the sodium salt of a 12-carbon alcohol that has been esterified to sulfuric acid. An alternative description is that it is an alkyl group with a pendant, terminal sulfate group attached. As a result of its hydrocarbon tail, and its anionic 'head group', it has amphiphilic properties that allow it to form micelles, and so act as a detergent. The critical micelle concentration (CMC) in pure water at 25 °C is 8.2 mM, and the aggregation number at this concentration is usually considered to be about 62. The micelle ionization fraction (α) is around 0.3 (or 30%). SDS is synthesized by treating lauryl alcohol with sulfur trioxide gas, oleum, or chlorosulfuric acid to produce hydrogen lauryl sulfate. The resulting product is then neutralized through the addition of sodium hydroxide or sodium carbonate. Lauryl alcohol can be used in pure form or may be derived from either coconut or palm kernel oil by hydrolysis (which liberates their fatty acids), followed by hydrogenation. When produced from these sources, commercial samples of these 'SDS' products are actually not pure SDS, rather a mixture of various sodium alkyl sulfates with SDS being the main component. For instance, SDS is a component, along with other chain-length amphiphiles, when produced from coconut oil, and is known as sodium coco sulfate (SCS). SDS is available commercially in powder, pellet, and other forms (each differing in rates of dissolution), as well as in aqueous solutions of varying concentrations. SDS is mainly used in detergents for laundry with many cleaning applications. It is a highly effective surfactant and is used in any task requiring the removal of oily stains and residues; for example, it is found in higher concentrations with industrial products including engine degreasers, floor cleaners, and car wash soaps. In lower concentrations, it is found in toothpastes, shampoos, shaving creams, and bubble bath formulations, for its ability to create a foam (lather), for its surfactant properties, and in part for its thickening effect. Sodium dodecyl sulfate, appearing as its synonym sodium lauryl sulfate (SLS), is considered as a generally recognized as safe (GRAS) ingredient, for food use according to the guidelines published in 21 CFR 172.822. It is used as an emulsifying agent and whipping aid. SLS is reported to temporarily diminish perception of sweetness. Sodium lauryl sulfate, in science referred to as sodium dodecyl sulfate (SDS), is used in cleaning procedures, and is commonly used as a component for lysing cells during RNA extraction and/or DNA extraction, and for denaturing proteins in preparation for electrophoresis in the SDS-PAGE technique. In the case of the SDS-PAGE application, the compound works by disrupting non-covalent bonds in the proteins, and so denaturing them, i.e., causing the protein molecules to lose their native conformations and shapes. By binding to the proteins with high affinity and in high concentrations, the negatively charged detergent provides all proteins with a similar net negative charge and therefore a similar charge-to-mass ratio. In this way, the difference in mobility of the polypeptide chains in the gel can be attributed solely to their size as opposed to both their size and charge. It is possible to make separation based on the size of the polypeptide chain to simplify the analysis of protein molecules, this can be achieved by denaturing proteins with the detergent SDS. The association of SDS molecules with protein molecules imparts an associated negative charge to the molecular aggregate formed; this negative charge is significantly greater than the original charge of that protein. The electrostatic repulsion that is created by SDS binding forces proteins into a rod-like shape, thereby eliminating differences in shape as a factor for electrophoretic separation in gels. Dodecyl sulfate molecule has two negative charges at the pH value used for electrophoresis, this will lead the net charge of coated polypeptide chains to be much more negative than uncoated chains. The charge-to-mass ratio is essentially identical for different proteins because SDS coating dominates the charge.