Ether
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Ethane,1,1¢-oxybis-.
Ethyl ether [60-29-7].
»Ether contains not less than 96.0percent and not more than 98.0percent of C4H10O,the remainder consisting of alcohol and water.
Caution—Ether is highly volatile and flammable.Its vapor,when mixed with air and ignited,may explode.
NOTE—Ether to be used for anesthesia must be preserved in tight containers of not more than 3-kg capacity,and is not to be used for anesthesia if it has been removed from the original container longer than 24hours.Ether to be used for anesthesia may,however,be shipped in larger containers for repackaging in containers as directed above,provided the ether at the time of repackaging meets the requirements of the tests of this Pharmacopeia.
Packaging and storage—
Preserve in partly filled,tight,light-resistant containers,at a temperature not exceeding 30
remote from fire.
remote from fire.
Labeling—
Where Ether is intended for anesthetic use,the label so states.
Acidity—
To 10mLof water in a glass-stoppered flask,add 0.10mLof bromothymol blue TSand 0.010Nsodium hydroxide until a blue color persists after vigorous shaking.Add 25mLof Ether,and shake briskly to mix the two layers.If no blue color remains,titrate with 0.010Nsodium hydroxide until the blue color is restored and persists for several minutes:not more than 0.80mLof 0.010Nsodium hydroxide is required (0.003%as CH3COOH).[NOTE—Exercise great care to avoid contamination from carbon dioxide when adding the Ether and titrating.]
Water,Method Iá921ñ:
not more than 0.5%,except where labeled as intended for anesthetic use,it contains not more than 0.2%.
Limit of nonvolatile residue—
Allow 50mLto evaporate spontaneously from a tared dish,and dry at 105for 1hour:the weight of the residue does not exceed 1mg (0.003%).
for 1hour:the weight of the residue does not exceed 1mg (0.003%).
Aldehyde—
Place 20mLin a glass-stoppered cylinder,and add 7mLof a mixture of 1mLof alkaline mercuric-potassium iodide TSand 17mLof a saturated solution of sodium chloride.Insert the stopper in the cylinder,shake vigorously for 10seconds,then set aside for 1minute:the water layer shows no turbidity.
Limit of peroxide—
Titanium tetrachloride solution—
Cool separately,in small beakers surrounded by crushed ice,10mLof 6Nhydrochloric acid and 10mLof titanium tetrachloride.Add the titanium tetrachloride dropwise to the chilled acid.Allow the mixture to stand at ice-bath temperature until all of the yellow solid dissolves,dilute the solution with 6Nhydrochloric acid to 1000mL,and mix.
Peroxide standard solution—
Pipet 25mLof hydrogen peroxide solution into a 1000-mLvolumetric flask,dilute with water to volume,and mix.Pipet 15mLof this solution into a 1000-mLvolumetric flask,dilute with water to volume,and mix.Each mLcontains 0.011mg of H2O2.
Procedure—
To 50mLof Ether,in a separator,add 5.0mLof Titanium tetrachloride solution.Shake vigorously,allow the layers to separate,and drain the lower layer into a glass-stoppered,25-mLgraduated cylinder.Dilute with water to 10.0mL,and mix.Any yellow color in the solution does not exceed that of a solution prepared by adding 5.0mLof Titanium tetrachloride solutionand 1.0mLof Peroxide standard solutionto a glass-stoppered,25-mLgraduated cylinder,diluting with water to 10.0mL,and mixing,the colors being determined in 1-cm cells,with a suitable spectrophotometer,at a wavelength of 410nm.The limit is 0.3ppm.
Low-boiling hydrocarbons—
Standard preparation—
Transfer about 50mLof anhydrous ethyl ether,previously tested for absence of hydrocarbons,as directed under Procedure,to a 100-mLvolumetric flask.Add 0.20mLof pentane,dilute with the same anhydrous ethyl ether to volume,and mix.
Apparatus—
Under typical conditions,a gas chromatograph (see Chromatography á621ñ)is equipped with a flame-ionization detector,and contains a 3.7-m ×2-mm (ID)stainless steel column packed with 30%phase G22on 30-to 60-mesh support S1C.The injector port,column,and detector are maintained at temperatures of about 230,80,and 250,respectively,nitrogen being used as the carrier gas at a flow rate of about 30mLper minute.
,80,and 250,respectively,nitrogen being used as the carrier gas at a flow rate of about 30mLper minute.
Procedure—
Inject 1µLof Standard preparationand Ether,respectively,into the apparatus,and measure the total area under the hydrocarbon peaks (under typical conditions the retention times are about 2.3minutes for isopentane,2.7minutes for pentane,and 4.3minutes for 2-methylpentane)in the Ether.The total area of the hydrocarbon peaks does not exceed that of the peak for pentane in the Standard preparation(0.2%).
Auxiliary Information—
Staff Liaison:Karen A Russo,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 788
Phone Number:1-301-816-8379