Sodium dodecyl sulfate

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"Sodium lauryl sulfate" redirects here. It is not to be confused with Sodium laureth sulfate.
Sodium lauryl sulfate
Sodium laurylsulfonate V.1.svg
SDS-sheet-3D-balls.png
Space-filling model of the sodium dodecyl sulfate crystal
Space-filling model of the dodecyl sulfate ion
Names
IUPAC name
Sodium lauryl sulfate
Other names
Sodium monododecyl sulfate; Sodium lauryl sulfate; Sodium monolauryl sulfate; Sodium dodecanesulfate; Sodium coco-sulfate; dodecyl alcohol, hydrogen sulfate, sodium salt; n-dodecyl sulfate sodium; Sulfuric acid monododecyl ester sodium salt;
Identifiers
151–21–3 YesY
ChEBI CHEBI:8984 YesY
ChEMBL ChEMBL23393 YesY
ChemSpider 8677 YesY
DrugBank DB00815 YesY
Jmol 3D model Interactive image
PubChem 3423265
  • InChI=1S/C12H26O4S.Na/c1-2-3-4-5-6-7-8-9-10-11-12-16-17(13,14)15;/h2-12H2,1H3,(H,13,14,15);/q;+1/p-1 YesY
    Key: DBMJMQXJHONAFJ-UHFFFAOYSA-M YesY
  • InChI=1S/C12H26O4S.Na/c1-2-3-4-5-6-7-8-9-10-11-12-16-17(13,14)15;/h2-12H2,1H3,(H,13,14,15);/q;+1/p-1
  • Key: DBMJMQXJHONAFJ-UHFFFAOYSA-M
  • CCCCCCCCCCCCOS(=O)([O-])=O.[Na+]
Properties
NaC12H25SO4
Molar mass 288.372 g/mol
Appearance white or cream-colored solid
Odor odorless
Density 1.01 g/cm3
Melting point 206 °C (403 °F; 479 K)
1.461
Pharmacology
ATC code A06AG11
Vapor pressure {{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Sodium dodecyl sulfate (SDS or NaDS), sodium laurilsulfate or sodium lauryl sulfate (SLS) is an organic compound with the formula CH3(CH2)11SO4Na. It is an anionic surfactant used in many cleaning and hygiene products. The salt is of an organosulfate consisting of a 12-carbon tail attached to a sulfate group, giving the material the amphiphilic properties required of a detergent. Derived from inexpensive coconut and palm oils, it is a common component of many domestic cleaning products.

Production

SDS is synthesized by treating lauryl alcohol with sulfur trioxide gas, oleum, or chlorosulfuric acid to produce hydrogen lauryl sulfate. The industrially practiced method typically uses sulfur trioxide gas. The resulting product is then neutralized through the addition of sodium hydroxide or sodium carbonate. Lauryl alcohol is in turn usually derived from either coconut or palm kernel oil by hydrolysis, which liberates their fatty acids, followed by hydrogenation.

Due to this synthesis method, commercial samples of SDS are often a mixture of other alkyl sulfates, dodecyl sulfate being the main component.[1]

SDS is available commercially in powder and pellet forms. It seems the pellet form dissolves faster than the powder form in water.[2]

Applications

Cleaning and hygiene

SDS is mainly used in detergents for laundry with many cleaning applications.[3] SDS 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. It is found in toothpastes, shampoos, shaving creams, and bubble bath formulations in part for its thickening effect and its ability to create a lather.[4] Pepsodent toothpaste at one time used the name "Irium" for its sodium lauryl sulfate ingredient.

Laboratory applications

Bottle of solution of sodium dodecyl sulfate for use in the laboratory.

It can be used to aid in lysing cells during DNA extraction and for unraveling proteins in SDS-PAGE. Sodium lauryl sulfate, in science referred to as sodium dodecyl sulfate (SDS) or Duponol, is commonly used in preparing proteins for electrophoresis in the SDS-PAGE technique.[5] This compound works by disrupting non-covalent bonds in the proteins, denaturing them, and causing the molecules to lose their native shape (conformation).

This new negative charge is significantly greater than the original charge of that protein. The electrostatic repulsion that is created by binding of SDS causes proteins to unfold into a rod-like shape thereby eliminating differences in shape as a factor for separation in the gel.

Sodium lauryl sulfate is probably the most researched anionic surfactant compound. Like all detergent surfactants, sodium lauryl sulfate removes oils from the skin, and can cause skin and eye irritation. The critical micelle concentration (CMC) in pure water at 25 °C is 8.2 mM,[6] and the aggregation number at this concentration is usually considered to be about 62.[7] The micelle ionization fraction (α) is around 0.3 (or 30%).[8]

Aqueous solutions of SDS are also popular for dispersing or suspending nanotubes, such as carbon nanotubes (CNTs). However, sodium dodecylbenzene sulfonate (NaDDBS) and Triton X-100 are reported to be better dispersants of single walled carbon nanotubes.[9]

Sodium lauryl sulfate is also used in the analysis of hemoglobin. The hydrophobic group of SLS acts upon the globin subunit, causing a conformational change. The hydrophilic group of SLS then binds with the oxidized iron subunit, producing a stable reaction product which can then be analyzed, giving a hemoglobin value which is used as part of a complete blood count.

Sodium dodecyl sulfate is also used to clear brain tissue, by removing lipids responsible for light scattering. Biological tissues treated by sodium dodecyl sulfate are rendered quasi-transparent in optical microscopy, enabling to see through them.[10]

Niche uses

Biocide

SDS represents a potentially effective topical microbicide, which can also inhibit and possibly prevent infection by various enveloped and non-enveloped viruses such as the Herpes simplex viruses, HIV, and the Semliki Forest Virus.[11][12]

Pesticide

SDS is an EPA approved inert ingredient for pesticide formulations.[13] It is also considered a Minimum Risk Pesticides Exempted from FIFRA Registration by the EPA under 40 CFR 152.25(f).

Food additive

It is used under the name sodium lauryl sulfate in some food products as an emulsifying agent and whipping aid.[14] It is considered generally recognized as safe (GRAS) for food use when used according to the guidelines published in 21 CFR 172.822.[15]

Taste alteration

Sodium lauryl sulfate temporarily diminishes perception of sweetness,[16] an effect commonly observed after recent use of toothpaste containing this ingredient.[17]

Toxicology

Carcinogenicity

SDS is not carcinogenic when either applied directly to skin or consumed.[18] A review of the scientific literature stated "SLS [SDS] was negative in an Ames (bacterial mutation) test, a gene mutation and sister chromatid exchange test in mammalian cells, as well as in an in vivo micronucleus assay in mice. The negative results from in vitro and in vivo studies indicate SDS does not interact with DNA."[19] The same review also stated "In the only carcinogenicity study available, SDS was not carcinogenic in Beagle dogs, though the short study duration and limited details provided limit the significance that can be attached to the data."

Sensitivity

It has been shown to irritate the skin of the face, with prolonged and constant exposure (more than an hour) in young adults.[20] SDS may worsen skin problems in individuals with chronic skin hypersensitivity, with some people being affected more than others.[21][22][23] In animal studies SDS appears to cause skin and eye irritation.[19]

SDS can contact the face from aerosolized dust when using SDS in its powder form in the laboratory. To prevent contact with face and eyes, a dust-free “pellet” form of SDS is available which essentially eliminates SDS dust inhalation and contact with the face.

Aphthous ulcers

There have been several studies on how SDS in toothpaste affects the recurrence of aphthous ulcers, commonly referred to in some countries as canker sores or white sores. The results of these studies have been inconsistent.

In 1994, a preliminary crossover study showed patients had a significantly higher number of aphthous ulcers after using SLS-containing toothpaste, compared with an SLS-free toothpaste.[24] A follow-up double-blind crossover study in 1996 further supported these results,[25] as did a separate study in 1997.[26]

However, a double-blind crossover study published in 1999 failed to find any statistically significant difference.[27] A double-blind crossover study in 2012 also failed to find a significant difference in number of ulcers, but did find a significant difference in ulcer duration and pain scores.[28] According to the 2012 study, patients using an SLS-free toothpaste experienced faster healing of ulcers and less ulcer-related pain on average than patients using SLS-containing toothpaste.[28]

Interaction with fluoride

Some studies have suggested that SLS in toothpaste may decrease the effectiveness of fluoride at preventing dental caries (cavities). This may be due to SLS interacting with the deposition of fluoride on tooth enamel.[29]

See also

References

  1. ↑ European Pharmacopoeia: Sodium laurilsulfate
  2. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Eduard Smulders, Wolfgang Rybinski, Eric Sung, Wilfried Rähse, Josef Steber, Frederike Wiebel, Anette Nordskog, "Laundry Detergents" in Ullmann’s Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a08_315.pub2
  4. ↑ Household Products Database of products containing sodium lauryl sulfate
  5. ↑ The acronym expands to "sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
  6. ↑ P. Mukerjee and K. J. Mysels, "Critical Micelle Concentration of Aqueous Surfactant Systems", NSRDS-NBS 36, US. Government Printing Office, Washington, D.C., 197 1.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  13. ↑ United States Environmental Protection Agency website http://iaspub.epa.gov/sor_internet/registry/substreg/searchandretrieve/advancedsearch/externalSearch.do?p_type=SRSITN&p_value=162032#
  14. ↑ IGOE, R. S. (1983). Dictionary of food ingredients. New York, Van Nostrand Reinhold Co.
  15. ↑ U.S. Government Publishing office 21 CFR 172.822 - Sodium lauryl sulfate. http://www.gpo.gov/fdsys/granule/CFR-2013-title21-vol3/CFR-2013-title21-vol3-sec172-822
  16. ↑ Adams, Michael J. Characterization and Measurement of Flavor Compounds: Substances That Modify the Perception of Sweetness. ACS Publications, 1985, p.11-25. Abstract online at http://pubs.acs.org/doi/abs/10.1021/bk-1985-0289.ch002
  17. ↑ Clark, Josh. "Why does orange juice taste bad after you brush your teeth?" Discovery Health. http://health.howstuffworks.com/wellness/beauty-hygiene/orange-juice-toothpaste.htm
  18. ↑ Lua error in package.lua at line 80: module 'strict' not found..
  19. ↑ 19.0 19.1 NICNAS – Sodium Lauryl Sulfate
  20. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  21. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  22. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  23. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  24. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  25. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  26. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  27. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  28. ↑ 28.0 28.1 Lua error in package.lua at line 80: module 'strict' not found.
  29. ↑ Lua error in package.lua at line 80: module 'strict' not found.
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