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viscous liquid

Polyethylene glycol sorbitan monolaurate, Polyoxyethylenesorbitan monolaurate
CAS Number:
MDL number:

Quality Level




≥40.0% (GC)


viscous liquid

mol wt



lauric acid, ≥40% (balance primarily myristic, palmitic, and stearic acids)


DNA extraction: suitable
RNA extraction: suitable
cell culture | mammalian: suitable
protein purification: suitable


≤3.0% water

refractive index

n20/D 1.468 (lit.)


0.06 mM (20-25°C)

acid number

≤2.2 mg/g

hydroxyl value

96‑108 mg/g

transition temp

cloud point 76 °C


1.095 g/mL at 25 °C (lit.)




complies for IR spectroscopy



InChI key


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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 a nonionic detergent widely used in biochemical applications. It has been used as an emulsifying agent for the preparation of stable oil-in-water emulsions. TWEEN 20 has been used in pre-extraction of membranes to remove peripheral proteins (used at 2% for extraction of membrane-bound proteins).
TWEEN 20 has been used as a blocking agent for membrane based immunoassays at a typical concentration of 0.05%. TWEEN 20 can be used for lysing mammalian cells at a concentration of 0.005 to 0.5%.
TWEEN 20 has been used as a component of:
  • washing buffer and blocking buffer in Western blotting
  • blocking buffer in immunohistochemistry
  • washing buffer in ELISA (enzyme linked immunosorbent assay)
  • reaction mixture in PCR (polymerase chain reaction)
Non-ionic detergent


1, 4 L in poly bottle
25, 100, 250, 500, 6×500 mL in poly bottle
Each kit contains 3 x 100ML samples, each sample from a uniquely manufactured lot.

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

Storage Class Code

10 - Combustible liquids



Flash Point(F)

527.0 °F - Pensky-Martens closed cup

Flash Point(C)

275 °C - Pensky-Martens closed cup

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificate of Analysis

Enter Lot Number to search for Certificate of Analysis (COA).

Certificate of Origin

Enter Lot Number to search for Certificate of Origin (COO).

  1. What is the percentage of Tween 20 in Product P1379?

    P1379 is not diluted in any solvent. Thus it can be considered "100%" or the "neat" material.

  2. Can solutions of Product P1379, Tween® 20, be autoclaved?

    Increased temperature can lead to autoxidation of TWEEN 20 in solution. Autoclaving is not recommended without testing for changes in properties. TWEEN 20 may not be stable to autoclaving, particularly with metal cations in buffer solutions. TWEEN 20 is heat sensitive; it will darken when exposed to elevated temperatures. Autoclaving is done at the customer's risk.

  3. What is the source of Product P1379, Tween® 20? Is it from plant or animal source, or synthetic?

    Origin information on any lot of Tween 20 is specific to that lot, and can be found on its Certificate of Origin (CofO), which may be accessed on the Sigma-Aldrich website under its specific product and lot number.

  4. The appearance of Product P1379, Tween® 20, is clear dark yellow. Is this OK?

    Yes. The specifications for P1379 are "clear yellow to yellow green viscous liquid".

  5. Is Product P1379, Tween® 20, protease-free?

    We have not tested P1379 in quality control to be protease-free. There is a Molecular Biology grade of Tween 20, P9416, but this is not tested specifically for proteases either. P9416 is tested to be endonuclease-endonuclease free and to be ribonuclease-free.

  6. Which document(s) contains shelf-life or expiration date information for a given product?

    If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.

  7. How do I get lot-specific information or a Certificate of Analysis?

    The lot specific COA document can be found by entering the lot number above under the "Documents" section.

  8. How do I find price and availability?

    There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers.

  9. What is the Department of Transportation shipping information for this product?

    Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product. 

  10. My question is not addressed here, how can I contact Technical Service for assistance?

    Ask a Scientist here.

Ethylene and carbon dioxide production by developing strawberries show a correlative pattern that is indicative of ripening climacteric fruit.
Lannetta PM et al
Physiologia Plantarum, 127.2, 247-259 (2006)
Gene expression and immune response kinetics using electroporation-mediated DNA delivery to muscle.
Gr?nevik E et al
The journal of gene medicine, 7(2), 218-227 (2005)
Use of tRNA consensus primers to indicate subgroups of Pseudomonas solanacearum by polymerase chain reaction amplification.
Seal SE et al
Applied and Environmental Microbiology, 58(11), 3759-3761 (1992)
Polysorbates 20 and 80 used in the formulation of protein biotherapeutics: structure and degradation pathways.
Kerwin BA
J. Pharm. Pharm. Sci., 97(8), 2924-2935 (2008)
Human hypoblast formation is not dependent on FGF signalling.
Roode M et al
Developmental Biology, 361(2), 358-363 (2012)


Fluorescent in situ Hybridization (FISH)

Available Fluorescent in situ hybridization (FISH) procedures, reagents and equipment.


Solubilization of Membrane Proteins

This page shows how to solubilize membrane proteins with products from Cytiva.

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

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