Packaging and storage
Preserve in tight containers.
Identification
It responds to the tests for Aluminum á191ñand for Acetate á191ñ.
Limit of boric acid
Pipet 25mLinto 75mLof water in a conical flask.Add 3mLof phenolphthalein TS,then add 0.5Nsodium hydroxide VSfrom a buret until a faint pink color is obtained.Heat to boiling,and again neutralize.Add 150mLof glycerin to the neutralized solution,and titrate with 0.5Nsodium hydroxide VS.Perform a blank determination in a similar manner.From the volume of 0.5Nsodium hydroxide VSused after the addition of the glycerin,subtract the volume used in the blank.Each mLof 0.5Nsodium hydroxide is equivalent to 30.92mg of H3BO3.
Assay for aluminum oxide
Edetate disodium titrant
Prepare and standardize as directed in the
Assayunder
Ammonium Alum.
Procedure
Pipet 25mLof Topical Solution into a 250-mLvolumetric flask,add 5mLof hydrochloric acid,dilute with water to volume,and mix.Pipet 25mLof this solution into a 250-mLbeaker,and add,in the order named and with continuous stirring,25.0mLof Edetate disodium titrantand 20mLof acetic acidammonium acetate buffer TS,then heat the solution near the boiling point for 5minutes.Cool,and add 50mLof alcohol and 2mLof dithizone TS.Titrate the solution with 0.05Mzinc sulfate VSto a bright rose-pink color.Perform a blank determination,substituting water for the sample,and make any necessary correction.Each mLof 0.05MEdetate disodium titrantis equivalent to 2.549mg of Al2O3.
Assay for acetic acid
Pipet 20mLof Topical Solution into a Kjeldahl flask containing a mixture of 20mLof phosphoric acid and 150mLof water.Connect the flask to a condenser,the delivery tube from which dips beneath the surface of 50.0mLof 0.5Nsodium hydroxide VScontained in a receiving flask.Distill about 160mL,then remove the delivery tube from below the surface of the liquid,allow the distilling flask to cool,add 50mLof water,and distill an additional 40to 45mLinto the receiving flask.Add phenolphthalein TSto the distillate,and titrate the excess 0.5Nsodium hydroxide VSwith 0.5Nsulfuric acid VS.Each mLof 0.5Nsodium hydroxide is equivalent to 30.03mg of C2H4O2.