Identification—
A:
When moistened with hydrochloric acid, it imparts an intense crimson color to a nonluminous flame.
B:
It responds to the test for
Citrate 
191
.
Assay—
Standard preparation—
Transfer to a 100-mL volumetric flask about 30 mg of
USP Lithium Carbonate RS, accurately weighed. Add about 20 mL of water and 0.5 mL of hydrochloric acid, shake until dissolved, dilute with water to volume, and mix. Pipet 20 mL of the resulting solution into a 1000-mL volumetric flask, add about 800 mL of water and 20 mL of a suitable surfactant solution, appropriately diluted, dilute with water to volume, and mix.
Assay preparation—
Transfer about 800 mg of Lithium Citrate, accurately weighed, to a 1000-mL volumetric flask. Dissolve in water, add 0.5 mL of hydrochloric acid, dilute with water to volume, and mix. Pipet 20 mL of this solution into a 1000-mL volumetric flask, add about 800 mL of water and 20 mL of the surfactant solution, dilute with water to volume, and mix.
Procedure—
Employ a suitable flame photometer, and adjust the instrument with the surfactant solution. Aspirate into the instrument the
Standard preparation and the
Assay preparation, and measure the emission at about 671 nm. Calculate the quantity, in mg, of C
6H
5Li
3O
7 in the portion of Lithium Citrate taken by the formula:
(419.84 / 221.67)(50C)(A / S),
in which 419.84 is twice the molecular weight of anhydrous lithium citrate, 221.67 is three times the molecular weight of lithium carbonate;
C is the concentration, in µg per mL, of
USP Lithium Carbonate RS in the
Standard preparation; and
A and
S are the photometer readings of the
Assay preparation and the
Standard preparation, respectively.
;)
for 3 hours: it loses between 24.0% and 28.0% of its weight.