Monosodium Glutamate
»Monosodium Glutamate contains not less than 99.0percent and not more than 100.5percent of C5H8NNaO4·H2O.
Packaging and storage—
Preserve in tight containers.
Clarity and color of solution—
Dissolve 1.0g in 10mLof water.The solution is colorless and has no more turbidity (see Visual Comparisonunder Spectrophotometry and Light-scattering á851ñ)than a standard mixture prepared as follows.To 0.2mLof a solution of sodium chloride containing 10µg of chloride ion (Cl)per mL,add 20mLof water,and mix,then add 1mLof 5Nnitric acid,0.2mLof dextrin solution (1in 50),and 1mLof silver nitrate TS,and allow to stand for 15minutes.
Identification—
A:
To 1mLof a solution (1in 30)add 1mLof ninhydrin TSand 100mg of sodium acetate,and heat in a boiling water bath for 10minutes:an intense,violet blue color is formed.
B:
To 10mLof a solution (1in 10)add 5.6mLof 1Nhydrochloric acid:a white,crystalline precipitate of glutamic acid is formed on standing.Precipitation is promoted by agitation.When 6mLof 1Nhydrochloric acid is added to the turbid solution,the glutamic acid dissolves on stirring.
C:
It responds to the pyroantimonate precipitate test for Sodium á191ñ.
Specific rotation á781Sñ:
between +24.8
and +25.3(t=20).
and +25.3(t=20).
Test solution:
100mg per mL,in 2Nhydrochloric acid.
pHá791ñ:
between 6.7and 7.2,in a solution (1in 20).
Loss on drying á731ñ—
Dry it at 100for 5hours:it loses not more than 0.5%of its weight.
for 5hours:it loses not more than 0.5%of its weight.
Chloride á221ñ—
A280-mg portion shows no more chloride than corresponds to 1.0mLof 0.020Nhydrochloric acid (0.25%).
Lead á251ñ:
10ppm.
Heavy metals,Method IIá231ñ:
0.002%.
Organic volatile impurities,Method Iá467ñ:
meets the requirements.
Assay—
Dissolve about 250mg of Monosodium Glutamate,accurately weighed,then wetted with a few drops of water,in 100mLof glacial acetic acid.Titrate with 0.1Nperchloric acid VS,determining the endpoint potentiometrically.Each mLof 0.1Nperchloric acid is equivalent to 9.356mg of C5H8NNaO4·H2O.
Auxiliary Information—
Staff Liaison:Karen A Russo,Ph.D.,Scientist
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 3040
Pharmacopeial Forum:Volume No.28(3)Page 826
Phone Number:1-301-816-8379