Hot Sale Cosmetic Raw Material Tween 20/60/80 CAS 9005-64-5 Emulsifier Polysorbate 20 60 80

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Tween 20, also known as Polysorbate 20, is a widely used nonionic surfactant in scientific research and industrial applications. It belongs to the polysorbate family and is chemically described as polyoxyethylene sorbitan monolaurate. With a CAS number of 9005-64-5, Tween 20 has become an essential reagent in molecular biology, biochemistry, and pharmaceutical laboratories worldwide .

Chemical Structure and Properties

Tween 20 is synthesized through the ethoxylation of sorbitol and its dehydration compounds (sorbitan) with approximately 20 moles of  in an alkaline environment, followed by esterification . The molecule has a molecular weight of approximately 1,225 Daltons and contains 20  units, one sorbitol ring, and one lauric acid as the primary fatty acid component . The compound appears as a colorless to pale yellow viscous liquid that is soluble in water at concentrations up to 100 mg/mL, producing a clear solution. It has a refractive index of approximately 1.468 and a density of 1.502 g/cm³. Tween 20 is insoluble in liquid paraffin and fixed oils.

Laboratory Applications

In laboratory settings, Tween 20 serves multiple critical functions. It is extensively used as a blocking agent in immunodetection assays at typical concentrations of 0.05%, particularly in Western blotting and ELISA procedures . The surfactant is also employed to remove peripheral proteins from membranes during pre-extraction steps, typically at 2% concentration for extracting membrane-bound proteins. In immunohistochemistry techniques, Tween 20 is commonly diluted with phosphate-buffered saline (PBS) to dilute antibodies, improving antibody penetration and reducing background noise.

Additionally, Tween 20 is used in fluorescence in situ hybridization (FISH) techniques for cell washing procedures. In Western blotting, 0.1% Tween 20 solutions are frequently used for washing PVDF or nitrocellulose membranes to remove unbound antibodies . For practical use, researchers typically prepare stock solutions at 10-20% concentration and dilute them to the required working concentration immediately before use.

Safety and Storage Considerations

Tween 20 is relatively stable under normal laboratory conditions but requires careful handling. It is sensitive to heat and may darken when exposed to elevated temperatures. Autoclaving is not recommended, especially in buffer solutions containing metal cations, as it may cause property changes . The compound is incompatible with alkalis, heavy metal salts, phenols, and tannic acids. Furthermore, aqueous solutions of Tween 20 may undergo auto-oxidation during storage, a process catalyzed by light, increased temperature, and copper sulfate.

Industrial and Pharmaceutical Uses

Beyond laboratory applications, Tween 20 functions as an emulsifier for preparing stable oil-in-water emulsions in food, cosmetic, and pharmaceutical industries. It is also used as an anti-foaming agent in cell culture and as a component in drug delivery systems due to its ability to enhance solubility and stability of various compounds .