P9416 Sigma-Aldrich


for molecular biology, viscous liquid

Synonym: Polyethylene glycol sorbitan monolaurate, Polyoxyethylenesorbitan monolaurate



Related Categories Antigen-Vaccine Preparation, Biochemicals, Biochemicals and Reagents, Cell Culture, Core Bioreagents,
grade   for molecular biology
description   non-ionic
assay   ≥40.0% (GC)
form   viscous liquid
mol wt   ~1228
composition   lauric acid, ≥40% (balance primarily myristic, palmitic, and stearic acids)
refractive index   n20/D 1.468 (lit.)
CMC   60 mg/L
density   1.095 g/mL at 25 °C (lit.)
suitability   suitable for molecular biology
foreign activity   Endonuclease-exonuclease and RNase, none detected
InChI   1S/C26H50O10/c1-2-3-4-5-6-7-8-9-10-11-24(30)34-19-18-31-20-22(32-15-12-27)26-25(35-17-14-29)23(21-36-26)33-16-13-28/h22-23,25-29H,2-21H2,1H3


General description

Tween®20 is a polyoxyethylene sorbitol ester that belongs to the polysorbate family. It is a nonionic detergent having a molecular weight of 1,225 daltons, assuming 20 ethylene oxide units, 1 sorbitol, and 1 lauric acid as the primary fatty acid. The ethylene oxide subunits are responsible for the hydrophilic nature of the surfactant, while the hydrocarbon chains provide the hydrophobic environment. Sorbitol forms the backbone ring to which the ethylene oxide polymers are attached.


TWEEN 20 is widely used in biochemical applications. It has been used:
• As an emulsifying agent for the preparation of stable oil-in-water emulsions
• In pre-extraction of membranes to remove peripheral proteins (used at 2% for extraction of membrane-bound proteins)
• As a blocking agent for membrane based immunoassays at a typical concentration of 0.05%
• For lysing mammalian cells at a concentration of 0.005 to 0.5%
• Along with PBS in the dilution of antibodies in immunohistochemistry technique
• For washing cells in FISH (Fluorescence in situ hybridization) technique

Non-ionic detergent


50, 100 mL in poly bottle


TWEEN 20 may not be stable to autoclaving, particularly with metal cations in buffer solutions. Autoclaving is not recommended without testing for changes in properties. TWEEN 20 is heat sensitive and will darken when exposed to elevated temperatures. Polysorbates have been reported to be incompatible with alkalis, heavy metal salts, phenols, and tannic acid. They may also reduce the activity of many preservatives. Aqueous solutions of polysorbates undergo autoxidation during storage, with changes being catalyzed by light, increased temperature, and copper sulfate.

Preparation Note

TWEEN 20 is miscible in water (100mg/mL), yielding a clear, yellow solution. It is also miscible with alcohol, dioxane, and ethyl acetate. TWEEN 20 is insoluble in liquid paraffin and fixed oils.

Legal Information

TWEEN is a registered trademark of Croda International PLC

Safety & Documentation

Safety Information

Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
527.0 °F - Pensky-Martens closed cup
Flash Point(C) 
275 °C - Pensky-Martens closed cup

pHast Pack
Protocols & Articles


Introduction to Western Blotting

The transfer of macromolecules such as nucleic acids and proteins to solid-phase membranous support is termed as blotting. Proteins resolved on Sodium dodecyl sulfate - polyacrylamide gel electrophor...
Keywords: Buffers, Cell disruption, Detergents, Electroblotting, Electrophoresis, Gel electrophoresis, Homogenization, Immobilization, PAGE, Protein assay, Protein extraction, Sample preparations, Separation, Size-exclusion chromatography, Western blot

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The biochemicals you use in your experiments directly impact the quality and reproducibility of your results. Biochemicals from us are world class products, competitively priced, and backed by superi...
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Peer-Reviewed Papers


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