Description: Tweens® are a series of nonionic surfactants derived from sorbitan esters. They are soluble or dispersible in water but differ widely in organic and oil solubilities. Used as oil-in-water emulsifiers in pharmaceuticals, cosmetics, cleaning compounds, etc. (Not sold by MP for human use).
~70% oleic acid (remainder primarily elaidic, linolenic and palmitic acids)
Specific Gravity
~1.1 g/ml
~1.08 g/ml
~1.1 g/ml
~1.08 g/ml
~1.0 g/ml
Viscosity @ 25°C
400 cps
600 cps
--
400 cps
300 cps
Acid No.
0-2.0
0-2.0
0-2.0
0-2.0
0-2.0
Saponification No.
40-50
43-49
45-55
45-55
83-93
Hydroxyl No.
96-108
89-105
81-96
65-80
39-52
Water
2.5-3.0%
2.5-3.0%
2.5-3.0%
2.5-3.0%
4.8-5.2%
Critical Micelle Concen. (CMC)
0.06 mM
(60 mg/L or
6 × 10-3 mole/L)
--
--
0.012 mM
(13-15 mg/L)
--
Molecular Weight
1228
--
1311.7
1310
--
Physical Description: Yellow, oily liquid
Typical Usage:
Polysorbate 20 is typically used as an emulsifying agent for the preparation of stable oil-in-water emulsions, particularly in pharmaceutical applications.17 Polysorbate 20 has been used in pre-extraction of membranes to remove peripheral proteins (used at 2% for extraction of membrane-bound proteins).1,10,12 Several resources may be helpful in determining usage concentrations.8,9,14 Polysorbate 20 has been used as a blocking agent on nitrocellulose at a typical concentration of 0.05%.
Tween® 40 can be used as a non-ionic detergent in cell lysis, nuclei isolation and cell fractionation.2,13,15
Tween® 80 has been widely used in biochemical applications including: solubilizing proteins, isolating nuclei from cells in culture4,7,15, selective protein extraction4,15, growing of tubercule bacilli6, and emulsifying and dispersing substances in medicinal and food products. It has little or no activity as an anti-bacterial agent.3 It has been shown to have an adverse effect on the antibacterial effect of methyl paraben and related compounds.16
Critical Micelle Concentration (CMC): Detergents with high CMC values are generally easy to remove by dilution; detergents with low CMC values are advantageous for separations on the basis of molecular weight. As a general rule, detergents should be used at their CMC and at a detergent-to-protein weight ratio of approximately ten. 19-20
Solubility: Soluble/miscible in water to give a clear yellow solution; miscible with alcohol, dioxane, and ethyl acetate; practically insoluble in liquid paraffin and fixed oils (such as mineral oil).17 Autoclaving of solutions is not recommended. Sterile filtering is suggested with a 0.22 micron filter. Tween® may need to be warmed to about 40°C and alternated with portions of hot distilled water while being poured through the filter.
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