Sodium dodecyl sulfate

Not to be confused with Sodium laureth sulfate.

Sodium lauryl sulfate
IUPAC name Sodium lauryl sulfate
Other names Sodium monododecyl sulfate; Sodium lauryl sulfate; Sodium monolauryl sulfate; Sodium dodecanesulfate; dodecyl alcohol, hydrogen sulfate, sodium salt; n-dodecyl sulfate sodium; Sulfuric acid monododecyl ester sodium salt;
Identifiers
CAS number	151-21-3 Y
ChemSpider	8677 Y
DrugBank	DB00815
ChEBI	CHEBI:8984 N
ChEMBL	CHEMBL23393 Y
ATC code	A06AG11
Jmol-3D images	Image 1
SMILES CCCCCCCCCCCCOS(=O)([O-])=O.[Na+]
InChI 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 Y Key: DBMJMQXJHONAFJ-UHFFFAOYSA-M Y 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
Properties
Molecular formula	NaC12H25SO4
Molar mass	288.38 g mol−1
Density	1.01 g/cm³
Melting point	206 °C
N dodecyl sulfate (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sodium dodecyl sulfate (SDS or NaDS), sodium laurilsulfate or sodium lauryl sulfate (SLS) is an organic compound with the formula CH₃(CH₂)₁₁OSO₃Na). 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. Being 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, or 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, commercially samples of SDS are often a mixture of other alkyl sulfates, dodecyl sulfate being the main component.^[1]

Applications

SDS is mainly used in detergents for laundry and many cleaning applications.^[2] 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 foams, and bubble bath formulations in part for its thickening effect and its ability to create a lather.^[3]

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.^[4] 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 (including soaps), 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 0.0082 M,^[5] and the aggregation number at this concentration is usually considered to be about 62.^[6] The micelle ionization fraction (α) is around 0.3 (or 30%).^[7] Aqueous solutions of SDS are also popular for dispersing (or suspending) nanotubes.

Niche uses

Biocide

SDS represent 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.^[8][9]

Medicinal applications

In medicine, sodium lauryl sulfate is used rectally as a laxative in enemas, and as an excipient on some dissolvable aspirins and other fiber therapy caplets.

Taste alteration

Sodium lauryl sulfate diminishes perception of sweetness,^[10] an effect commonly observed after recent use of toothpaste containing this ingredient.^[11]

Toxicology

Non-carcinogenicity

SDS is not carcinogenic when either applied directly to skin or consumed.^[12] 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."^[13]

Sensitivity

It has been shown to irritate the skin of the face with prolonged and constant exposure (more than an hour) in young adults.^[14] SDS may worsen skin problems in individuals with chronic skin hypersensitivity, with some people being affected more than others.^[15][16][17] In animal studies SDS appears to cause skin and eye irritation.^[13]

Aphthous ulcers

A preliminary study suggested SDS in toothpaste caused the recurrence of aphthous ulcers, commonly referred to in some countries as canker sores or white sores.^[18] The preliminary study "showed a statistically significant decrease in the number of aphthous ulcers from 14.3 after using the SLS-containing dentifrice to 5.1 ulcers after brushing with the SLS-free dentifrice."^[18] A clinical study comparing the incidence of recurrent aphthous ulcers during the use of dentifrices with and without sodium lauryl sulfate supported the findings of an earlier independent study which suggest that use of an SLS-free dentifrice should be considered for individuals who suffer from recurrent aphthous ulcers.^[19] A clinical double-blind crossover study found sodium lauryl sulfate had a significantly higher frequency of aphthous ulcers than both cocoamidopropyl betaine or a detergent-free paste, on 30 patients with frequent occurrences of recurrent aphthous ulcers.^[20] The clinical double-blind crossover study suggests use of an SLS-free toothpaste for patients with recurrent aphthous ulcers would reduce recurrence.^[20] A double-blind crossover trial comparing toothpastes with and without SLS found that it had no significant effect on ulcer patterns.^[21] Other studies indicate concerns regarding SLS in toothpaste.^[22]

See also

• Ammonium lauryl sulfate
• Sodium myreth sulfate

References

1. ^ European Pharmacopoeia: Sodium laurilsulfate
2. ^ 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
3. ^ Household Products Database of products containing sodium lauryl sulfate
4. ^ The acronym expands to "sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
5. ^ 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.
6. ^ N.J. Turro. A. Yekta, J. Am. Chem. Soc., 1978, 100, 5951
7. ^ Barney L. Bales, Luis Messina, Arwen Vidal, Miroslav Peric, and Otaciro Rangel Nascimento (1998). "Precision Relative Aggregation Number Determinations of SDS Micelles Using a Spin Probe. A Model of Micelle Surface Hydration". J. Phys. Chem. B 102 (50): 10347–10358. doi:10.1021/jp983364a. 
8. ^ Piret J, Désormeaux A, Bergeron MG. (2002). "Sodium lauryl sulfate, a microbicide effective against enveloped and nonenveloped viruses.". Curr Drug Targets 3 (1): 17–30. doi:10.2174/1389450023348037. PMID 11899262. 
9. ^ Piret J, Lamontagne J, Bestman-Smith J, Roy S, Gourde P, Désormeaux A, Omar RF, Juhász J, Bergeron MG. (2000). "In vitro and in vivo evaluations of sodium lauryl sulfate and dextran sulfate as microbicides against herpes simplex and human immunodeficiency viruses.". J Clin Microbiol 38 (1): 110–9. PMC 86033. PMID 10618073. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=86033. 
10. ^ 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
11. ^ 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
12. ^ CIR publication (1983). "Final Report on the Safety Assessment of Sodium Lauryl Sulfate and Ammonium Lauryl Sulfate". International Journal of Toxicology 2 (7): 127–181. doi:10.3109/10915818309142005. .
13. ^ ^{a b} NICNAS - Sodium Lauryl Sulfate
14. ^ Marrakchi S, Maibach HI (2006). "Sodium lauryl sulfate-induced irritation in the human face: regional and age-related differences". Skin Pharmacol Physiol 19 (3): 177–80. doi:10.1159/000093112. PMID 16679819. 
15. ^ Agner T (1991). "Susceptibility of atopic dermatitis patients to irritant dermatitis caused by sodium lauryl sulphate". Acta Derm. Venereol. 71 (4): 296–300. PMID 1681644. 
16. ^ Nassif A, Chan SC, Storrs FJ, Hanifin JM (November 1994). "Abnormal skin irritancy in atopic dermatitis and in atopy without dermatitis". Arch Dermatol 130 (11): 1402–7. doi:10.1001/archderm.130.11.1402. PMID 7979441. 
17. ^ Löffler H, Effendy I (May 1999). "Skin susceptibility of atopic individuals". Contact Derm. 40 (5): 239–42. doi:10.1111/j.1600-0536.1999.tb06056.x. PMID 10344477. 
18. ^ ^{a b} Herlofson BB, Barkvoll P (October 1994). "Sodium lauryl sulfate and recurrent aphthous ulcers. A preliminary study". Acta Odontol. Scand. 52 (5): 257–9. doi:10.3109/00016359409029036. PMID 7825393. 
19. ^ Chahine L, Sempson N, Wagoner C (December 1997). "The effect of sodium lauryl sulfate on recurrent aphthous ulcers: a clinical study". Compend Contin Educ Dent 18 (12): 1238–40. PMID 9656847. 
20. ^ ^{a b} Herlofson BB, Barkvoll P (June 1996). "The effect of two toothpaste detergents on the frequency of recurrent aphthous ulcers". Acta Odontol. Scand. 54 (3): 150–3. doi:10.3109/00016359609003515. PMID 8811135. 
21. ^ Healy CM, Paterson M, Joyston-Bechal S, Williams DM, Thornhill MH (1999 Jan). "The effect of a sodium lauryl sulfate-free dentifrice on patients with recurrent oral ulceration". Oral Dis. 5 (1): 39–43. doi:10.1111/j.1601-0825.1999.tb00062.x. PMID 10218040. 
22. ^ Should toothpastes foam? Sodium lauryl sulfate--a toothpaste detergent in focus.