Edetic Acid
;)
Glycine,N,N¢-1,2-ethanediylbis[N-(carboxymethyl)-.
(Ethylenedinitrilo)tetraacetic acid [60-00-4].
»Edetic Acid contains not less than 98.0percent and not more than 100.5percent of C10H16N2O8.
Packaging and storage—
Preserve in well-closed containers.
Identification,Infrared Absorption á197Kñ.
Residue on ignition á281ñ:
not more than 0.2%.
Heavy metals,Method IIá231ñ:
0.003%.
Iron—
Char 3.0g thoroughly,and heat in an oven at 500
until most of the carbon is consumed.Cool,add 0.15mLof nitric acid,and heat at 500until all of the carbon is consumed.Dissolve the residue in 2mLof a mixture of equal volumes of hydrochloric acid and water,digest in a covered dish on a steam bath for 10minutes,remove the cover,and evaporate to dryness.Dissolve the residue in 1mLof 1Nacetic acid and 20mLof hot water,digest for 5minutes on a steam bath,cool,and dilute with water to 30mL.To 2.0mLof this solution add 2mLof hydrochloric acid,and dilute with water to 50mL.Add about 50mg of ammonium persulfate and 3mLof ammonium thiocyanate solution (3in 10),mix,and transfer to a color-comparison tube.Treat in the same manner 2.0mLof a solution of ferric ammonium sulfate,prepared by dissolving 43.2mg of ferric ammonium sulfate in 10mLof 2Nsulfuric acid and adding water to make 1000mL,each mLrepresenting 5µg of Fe.The color of the test solution is not deeper than that of the solution containing the standard iron solution (0.005%).
until most of the carbon is consumed.Cool,add 0.15mLof nitric acid,and heat at 500until all of the carbon is consumed.Dissolve the residue in 2mLof a mixture of equal volumes of hydrochloric acid and water,digest in a covered dish on a steam bath for 10minutes,remove the cover,and evaporate to dryness.Dissolve the residue in 1mLof 1Nacetic acid and 20mLof hot water,digest for 5minutes on a steam bath,cool,and dilute with water to 30mL.To 2.0mLof this solution add 2mLof hydrochloric acid,and dilute with water to 50mL.Add about 50mg of ammonium persulfate and 3mLof ammonium thiocyanate solution (3in 10),mix,and transfer to a color-comparison tube.Treat in the same manner 2.0mLof a solution of ferric ammonium sulfate,prepared by dissolving 43.2mg of ferric ammonium sulfate in 10mLof 2Nsulfuric acid and adding water to make 1000mL,each mLrepresenting 5µg of Fe.The color of the test solution is not deeper than that of the solution containing the standard iron solution (0.005%).
Limit of nitrilotriacetic acid—
Mobile phase
,Cupric nitrate solution,Stock standard solution,and Chromatographic system—Prepare as directed in the test for Limit of nitrilotriacetic acidunder Edetate Disodium.
Resolution solution—
Using Edetic Acid instead of Edetate Disodium,prepare as directed for Resolution solutionin the test for Limit of nitrilotriacetic acidunder Edetate Disodium.
Standard preparation—
Transfer 1.0g of Edetic Acid to a 100-mLvolumetric flask,add 300µLof Stock standard solution,dilute with Cupric nitrate solutionto volume,and mix.Sonicate,if necessary,to achieve complete solution.
Test preparation—
Transfer 1.0g of Edetic Acid to a 100-mLvolumetric flask,dilute with Cupric nitrate solutionto volume,and mix.Sonicate,if necessary,to achieve complete solution.
Procedure—
Proceed as directed for Procedurein the test for Limit of nitrilotriacetic acidunder Edetate Disodium:the response of the nitrilotriacetic acid peak of the Test preparationdoes not exceed the difference between the nitrilotriacetic acid peak responses obtained from the Standard preparationand the Test preparation(0.3%).
Assay—
Assay preparation—
Transfer about 1.4g of Edetic Acid,accurately weighed,to a 100-mLvolumetric flask,dissolve in 11mLof 1Nsodium hydroxide,dilute with water to volume,with cooling,if necessary,and mix.
Procedure—
Transfer to a 400-mLbeaker about 200mg of chelometric standard calcium carbonate,previously dried at 110for 2hours,cooled in a desiccator,and accurately weighed.Add 10mLof water,swirl to form a slurry,and cover the beaker with a watch glass.Without removing the watch glass,add 2mLof 3Nhydrochloric acid from a pipet,and swirl to dissolve.Wash down the sides of the beaker,the outer surface of the pipet,and the watch glass with water,and dilute with water to about 100mL.While stirring with a magnetic stirrer,add about 30mLof the Assay preparationfrom a 50-mLburet.Add 10mLof 1Nsodium hydroxide and 300mg of hydroxy naphthol blue,and continue the titration with the Assay preparationto a blue endpoint.Calculate the weight,in g,of C10H16N2O8in the portion of Edetic Acid taken by the formula:
for 2hours,cooled in a desiccator,and accurately weighed.Add 10mLof water,swirl to form a slurry,and cover the beaker with a watch glass.Without removing the watch glass,add 2mLof 3Nhydrochloric acid from a pipet,and swirl to dissolve.Wash down the sides of the beaker,the outer surface of the pipet,and the watch glass with water,and dilute with water to about 100mL.While stirring with a magnetic stirrer,add about 30mLof the Assay preparationfrom a 50-mLburet.Add 10mLof 1Nsodium hydroxide and 300mg of hydroxy naphthol blue,and continue the titration with the Assay preparationto a blue endpoint.Calculate the weight,in g,of C10H16N2O8in the portion of Edetic Acid taken by the formula:
(292.24/100.09)(0.1W/V),
in which 292.24and 100.09are the molecular weights of edetic acid and calcium carbonate,respectively,Wis the weight,in mg,of calcium carbonate,and Vis the volume,in mL,of the Assay preparationconsumed in the titration.
Auxiliary Information—
Staff Liaison:Daniel K.Bempong,Ph.D.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 3002
Phone Number:1-301-816-8143