Everything about Sodium Lauryl Sulfate totally explained
| Section2 =
}}
Sodium lauryl sulfate (
SLS) or
sodium dodecyl sulfate (or
sulphate) (
SDS or NaDS) (
C12H25SO4Na) is an
anionic
surfactant that's used in household products such as
toothpastes,
shampoos,
shaving foams, some dissolvable
aspirins, fiber therapy caplets, and
bubble baths for its thickening effect and its ability to create a lather. The molecule has a tail of 12 carbon atoms, attached to a
sulfate group, giving the molecule the
amphiphilic properties required of a
detergent.
It is prepared by
esterification of
sulfuric acid with
dodecanol (lauryl alcohol, C
12H
25OH) followed by neutralization with
sodium carbonate. It is used in both industrially produced and home-made cosmetics.
Like all
detergent surfactants (including
soaps), it removes oils from the
skin, and can cause skin and eye irritation.
SLS can be converted by
ethoxylation to
sodium laureth sulfate (also called sodium lauryl ether sulfate; SLES), which is less harsh on the skin, probably because it isn't as much of a protein denaturant as is the unethoxylated substance.
It is probably the most researched anionic surfactant compound.
It has recently found application as a surfactant in
gas hydrate or
methane hydrate formation reactions, increasing the rate of formation as much as 700 times.
Biochemical applications
In laboratories, SLS is commonly used in preparing
proteins for
polyacrylamide gel electrophoresis (
SDS-PAGE). SLS works by disrupting non-covalent bonds in the proteins, thereby denaturing them, causing the molecules to lose their native shape (conformation). Also, anions of SLS bind to the main
peptide chain at a ratio of one SLS anion for every two
amino acid residues. This effectively imparts a negative charge on the
protein that's proportional to the mass of that protein (about 1.4 g SLS/g protein). This new negative charge is significantly greater than the original charge of that protein. The
electrostatic repulsion that's created by binding of SLS causes proteins to unfold into a rod-like shape thereby eliminating differences in shape as a factor for separation in the gel.
Safety concerns relating to SLS
When handling SLS in its solid form use extreme caution, the compound easily particalizes into the air. If inhaled can cause a serious choking hazard. It is strongly advised that a dust mask and vacuum hood be used when working with the compound to minimize exposure.
A number of health concerns about SLS have been raised in published reports. These studies indicate that:
- SLS may cause a number of skin problems (for which the non-specific term is dermatitis), with some people being affected more than others.
- SLS in toothpaste may cause aphthous ulcers, commonly referred to in some countries as "canker sores". However, some studies find no connection between SLS in toothpaste and mouth ulcers.
Data
The critical micelle concentration in pure water at 25°C is 0.0082 M, and the aggregation number at this concentration is usually considered to be about 50. The micelle ionization fraction (α) is around 0.3 (or 30%).
The Optical refractive index increment of a pure aqueous solution at wavelength 532 nm is about 0.1070 ml/g.Further Information
Get more info on 'Sodium Lauryl Sulfate'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://sodium_lauryl_sulfate.totallyexplained.com">Sodium lauryl sulfate Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |