C2H6O 46.07

Ethanol.
Ethyl alcohol [64-17-5].

Packaging and storage— Preserve in tight containers,remote from fire.

Identification—

Specific gravity á841ñ: not more than 0.7962at 15.56,indicating not less than 99.2%of C2H5OHby weight.

Acidity— To 50mL,in a glass-stoppered flask,add 50mLof recently boiled water.Add phenolphthalein TS,and titrate with 0.020Nsodium hydroxide to a pink color that persists for 30seconds:not more than 0.90mLof 0.020Nsodium hydroxide is required for neutralization.

Limit of nonvolatile residue— Evaporate 40mLin a tared dish on a water bath,and dry at 105for 1hour:the weight of the residue does not exceed 1mg.

Water-insoluble substances— Dilute it with an equal volume of water:the mixture is clear and remains clear for 30minutes after cooling to 10.

Aldehydes and other foreign organic substances— Place 20mLin a glass-stoppered cylinder that has been thoroughly cleaned with hydrochloric acid,then rinsed with water and finally with the Dehydrated Alcohol to be tested.Cool the contents to approximately 15,and add,by means of a carefully cleaned pipet,0.10mLof 0.10Npotassium permanganate,noting accurately the time of addition.Mix at once by inverting the stoppered cylinder,and allow it to stand at 15for 5minutes:the pink color does not entirely disappear.

Amyl alcohol and nonvolatile,carbonizable substances— Allow 25mLto evaporate spontaneously from a porcelain dish,carefully protected from dust,until the surface of the dish is barely moist:no red or brown color is produced immediately upon the addition of a few drops of sulfuric acid.

Ultraviolet absorbance— Record the UVabsorption spectrum between 340nm and 235nm in a 1-cm cell,with water in a matched cell in the reference beam:the absorbance is not more than 0.08at 240nm,and 0.02between 270nm and 340nm,and the curve drawn through these points is smooth.

Limit of acetone and isopropyl alcohol— To 1.0mLadd 1mLof water,1mLof a saturated solution of dibasic sodium phosphate,and 3mLof a saturated solution of potassium permanganate.Warm the mixture to 45to 50,and allow to stand until the permanganate color is discharged.Add 3mLof 2.5Nsodium hydroxide,and pass,without washing,through a sintered-glass filter.Prepare a control containing 1mLof the saturated solution of dibasic sodium phosphate,3mLof 2.5Nsodium hydroxide,and 80µg of acetone in 9mL.To each solution add 1mLof furfural solution (1in 100),and allow to stand for 10minutes,then to 1.0mLof each solution add 3mLof hydrochloric acid:any pink color produced in the test solution is not more intense than that in the control.

Methanol— To 1drop add 1drop of water,1drop of dilute phosphoric acid (1in 20),and 1drop of potassium permanganate solution (1in 20).Mix,allow to stand for 1minute,and add sodium metabisulfite solution (1in 20),dropwise,until the permanganate color is discharged.If a brown color remains,add 1drop of the dilute phosphoric acid.To the colorless solution add 5mLof freshly prepared chromotropic acid TS,and heat on a water bath at 60for 10minutes:no violet color appears.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 61

Phone Number:1-301-816-8323