P1379 Sigma-Aldrich


viscous liquid

Synonym: Polyethylene glycol sorbitan monolaurate, Polyoxyethylenesorbitan monolaurate



Related Categories Antigen-Vaccine Preparation, Biochemicals and Reagents, Buffers, Cell Biology, Cell Culture,
Quality Level   300
description   non-ionic
assay   ≥40.0% (GC)
form   viscous liquid
mol wt   ~1228
composition   lauric acid, ≥40% (balance primarily myristic, palmitic, and stearic acids)
application(s)   DNA extraction: suitable
  RNA extraction: suitable
  cell culture | mammalian: suitable
  protein purification: suitable
impurities   ≤3.0% water
refractive index   n20/D 1.468 (lit.)
CMC   0.06 mM (20-25°C)
acid number   ≤2.2 mg/g
hydroxyl value   96‑108 mg/g
transition temp   cloud point 76 °C
density   1.095 g/mL at 25 °C (lit.)
HLB   16.7
suitability   complies for IR spectroscopy
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 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)

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%.

Non-ionic detergent


1, 4 L in poly bottle

25, 100, 250, 500, 6×500 mL in poly bottle

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) 
>230 °F
Flash Point(C) 
>110 °C


Certificate of Analysis (COA)

Please Enter a Lot Number

Certificate of Origin (COO)

Please Enter a Lot Number

Frequently Asked Questions

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.
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.
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.
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".
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.
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.
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.
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.
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.
My question is not addressed here, how can I contact Technical Service for assistance?
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pHast Pack
Protocols & Articles


Fluorescent in situ Hybridization (FISH)

To search our entire portfolio of antibodies for your research needs, use our Antibody Explorer Tool.
Keywords: Nucleic acid hybridization, Polymerase chain reaction

Solubilization of Membrane Proteins

Extracted from Purifying Challenging Proteins - Principles and Methods, GE Healthcare, 2007
Keywords: Buffers, Cell disruption, Centrifugation, Chromatography, Crystallization, Degradations, Detergents, Dot blot, Enzyme activity, Filtration, Gene expression, Indicators, Ion Exchange, Ligands, PAGE, Purification, Separation, Solvents, Western blot

Peer-Reviewed Papers


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