H2SO4 98.08

Sulfuric acid.
Sulfuric acid [7664-93-9].

Packaging and storage— Preserve in tight containers.

Identification— It responds to the tests for Sulfate á191ñ.

Residue on ignition á281ñ— Evaporate 22mL(40g)to dryness,and ignite:not more than 2mg of residue remains (0.005%).

Chloride á221ñ— Adilution of 1.1mL(2.0g)in water shows no more chloride than corresponds to 0.15mLof 0.020Nhydrochloric acid (0.005%).

Arsenic á211ñ— Add 1.6mL(3.0g)to 3mLof nitric acid and 20mLof water,and evaporate until dense fumes of sulfur trioxide form.Cool,and cautiously wash the solution into an arsine generating flask with 50mLof water;the resulting solution meets the requirements of the test,the addition of 20mLof dilute sulfuric acid (1in 5)specified for Procedurebeing omitted (1ppm).

Heavy metals á231ñ— Add 2.2mL(4.0g)to about 10mg of sodium carbonate dissolved in 10mLof water.Heat until almost dry,add 1mLof nitric acid,evaporate to dryness,add 2mLof 1Nacetic acid to the residue,and dilute with water to 25mL:the limit is 5ppm.

Reducing substances— Carefully dilute 4.4mL(8.0g)with about 50mLof ice cold water,keeping the solution cold during the addition.Add 0.10mLof 0.10Npotassium permanganate:the solution remains pink for 5minutes.

Assay— Place about 1mLof Sulfuric Acid in an accurately weighed,glass-stoppered flask containing about 20mLof water,and weigh again to obtain the weight of the test specimen.Dilute with about 25mLof water,cool,add methyl orange TS,and titrate with 1Nsodium hydroxide VS.Each mLof 1Nsodium hydroxide is equivalent to 49.04mg of H2SO4.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 3096

Phone Number:1-301-816-8330