Denaturing agents methanol

Methanol is widely used as a solvent and as a denaturing agent for ethanol and is also found in antifreeze. Mass poisonings have occurred because of ingestion in alcoholic drinks made with contaminated ethanol as well as from accidental exposure. Inhalation and skin absorption may cause toxicity. In humans, about 10 mL can cause blindness and 30 mL is potentially fatal, but there is variation in the lethal dose. 

Superdex, Superose, Sephacryl and Sepharose CL are chemically relatively inert they can be used between pH 3 and 11, and will survive more extreme conditions (pH 2-12) for short periods. They are also resistant to a range of other conditions such as 1 % (w/v) SDS, chaotropic denaturing agents (6 M guanidinium hydrochloride or 8 M urea) as well as some organic solvents (e.g formamide, DMSO, methanol, ethanol and acetone). 

Synonyms industrial methylated spirit surgical spirit. Comments denatured alcohol is alcohol intended for external use only. It has been rendered unfit for human consumption by the addition of a denaturing agent such as methanol or methyl isobutyl ketone. 

As obtained synthetically, ethanol contains 4 wt.-% of water, as well as acetaldehyde and acetone. Alcohol obtained by fermentation contains also higher alcohols. Further impurities are the denaturing agents that are usually added (methanol, pyridine bases, petroleum). Absolute alcohol obtained commercially by azeotropic distillation may contain also traces of benzene or trichloroethylene. 

This proeess is relevant primarily to ethanol. Common denaturing agents are methanol, isopropanol, ethyl aeetate, toluene. 

The strength of alcohol commonly used in the US is 95% (190 proof), while 96% is used in Europe. For prepn of perfumes the 70% alcobol is used. TTie so-called absolute alcobol (200 proof) is at least 99% and its use is restricted. to analytical purposes or research. The so-called industrial alcohol is unfit to drink because it contains up to 5% methanol (wood alcohol) or benzene. Such alcohol is known as denatured and it is briefly described in Vol 3 of Encycl, p D63-R. Denatured alcohol is used as a solvent for expls, rocket fuels, rubbers, detergents, etc. Mixture of 1 part alcobol with 2 parts eth (described in Vol 5 of Encycl as Diethyl Ether) used as a solvent in dehydration of Pyrocellulose in manuf of single-base propint, such as described in Davis (Ref 2) and also on p C399 of Vol 3 of Encycl, under "Colloiding Agents and Colloidal Propellants ... 

If staining is used to visualize the separated proteins, the proteins are usually first fixed by precipitating them in the gel with a chemical agent like acetic acid and methanol. This prevents diffusion of proteins out of the gel when submersed in the stain solution. The amount of dye taken up by the sample is affected by many factors, such as the type of protein and the degree of denaturation of the proteins by the fixing agents. 

Organic solvents like methanol or acetone also can be used to open membranes, but they also act as denaturing fixatives. Solvents are used at -20 C for 10 min, but the use is not recommended. As described in previous sections, denaturing fixatives may cause loss of epitopes in the cells. Other detergent-like agents, such as saponin or digitonin, are used for transient permeabilization of cell cultures, and reversibly insert into and out of plasma membranes next to cholesterol. These agents must be present in all solutions after the fixative and should only be used for electron microscopy immunocytochemistry. 

Displacement drying uses anhydrous fluids, such as IPA (isopropanol), anhydrous ethyl alcohol denatured with acetone or methanol, or a commercial drying agent, to displace the... 

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