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chemical structure of SDS (sodium dodecyl sulphate)

SDS (sodium dodecyl sulfate/sulphate) is an anionic detergent effective in both acidic and alkaline solutions. SDS has a wide variety of applications, but is most often used in protein and lipid solubilisation.


  • highly flammable
  • harmful in contact with skin and if swallowed
  • irritating to eyes, respiratory system and skin

see MSDS

Chemical properties

  • water solubility: 250g/l at 20ºC
  • molecular weight MW: 288.38 g/mol

SDS solubilisation of biomolecules

As a rule of thumb for the solubilisation/solubilization of proteins, SDS should be used at its critical micelle concentration (Womack'83 PMID 6882760). For the effects of SDS on protein conformation see Protein Structure by Creighton [1]. For comparisons between SDS and other detergents for solubilisation of lipids, proteins, and its effect on enzymes activity see Womack '83 (PMID 6882760) and Creighton Protein Structure.

Critical micelle concentration CMC of SDS

CMC of SDS varies with pH. It is about 0.009 mol/L at pH 5-10. At more acidic pH the CMC drops off to about 0.007M at pH 2 (Rahman Brown '83 [2]).

Stability & Storage

SDS undergoes hydrolysis at higher temperatures especially in acidic medium. Prolonged heating at >40°C causes decomposition of alkyl sulphates into fatty alcohols and sodium sulphate.

SDS removal

Use an ion retardation columns to remove SDS from protein samples. Retardation Resin. For SDS removal methods see Kapp'78 (PMID 9762103) and similar papers [3]. Methylene blue can be used to determine the remaining amount of SDS.

See also