Sodium Chloride contains not less than 99.0 percent and not more than 101.0 percent of NaCl, calculated on the dried basis. It contains no added substance.  

Packaging and storage-Preserve in weIl-closed containers. 

Labeling- Where Sodium Chloride is intended for use in hemodialysis, it is so labeled. 

Identification: A solution (1 in 20) responds to the tests for Sodium and for Chloride. 

Acidity or alkalinity: Dissolve 50.0 g in 200 mL of carbon dioxide-free water, and add 10 drops of bromothymol blue pH indicator. If the solution is yellow, it requires not more than 1.0 mL of 0.020 N sodium hydroxide to produce a blue color. If the solution is blue or green, it requires not more than 3.12 mL of 0.020 N hydrochloric acid to produce a yellow color. 

Loss on drying:   Dry it at 105ºC for 2 hours: it loses not more than 0.5% of its weight. 

lodide or bromide: Digest 2.0 g of finely powdered Sodium Chloride with 25 mL of warm alcohol for 3 hours, cool the mixture, and remove the undissolved salt by filtration. Evaporate the filtrate to dryness, dissolve the residue in 5 mL of water, add 1 mL of chloroform, and cautiously introduce, dropwise, with constant agitation, 5 drops of dilute chlorine TS (1 in 3): the chloroform does not acquire a violet, yellow, or orange color. 

Aluminum:  (where it is labeled as intended for use in hemodialysis)- 
[NOTE-The Standard preparations and the Test preparation may be modified, if necessary, to obtain solutions of suitable concentrations adaptable to the linear or working range of the instrument.] 
Nitric acid diluent and Standard preparations-Prepare as directed in the test for Aluminum under Sodium Bicarbonate. 

Test preparation- Transfer 10.0 g of Sodium Chloride to a 100-mL plastic volumetric flask, add 50 mL of water, and sonicate for 30 minutes. Add 4 mL of nitric acid, dilute with water to volume, and mix. 

Procedure- Proceed as directed for Procedure in the test for Aluminum under Sodium Bicarbonate. Calculate the ppm of Al in the specimen taken by multiplying by 10 the quantity, in mg of aluminum found in each mL of the Test preparation: the limit is 0.2 ppm. 

Calcium and magnesium:  Dissolve 20 g in 200 mL of water, and add 0. 1 mL of hydrochloric acid, 5 mL of ammonia-ammonium chloride buffer TS, and 5 drops of eriochrome black TS. Titrate with 0.005 M disodium ethylenediaminetetraacetate VS to a pure blue endpoint. Each mL of 0.005 M disodium ethylenediaminetetraacetate is equivalent to 0.2004 mg of Ca. Not more than 0.005% of calcium and magnesium (as Ca) is found. 

Arsenic:  Method 1: 3 ppm. 

Iron:  Dissolve 5.0 g in 45 mL of water and 2 mL of hydrochloric acid: the limit is 2 ppm. 

Barium:  Dissolve 4.0 g in 20 mL of water, filter if necessary, and divide the solution into two portions. To one portion add 2 mL of 2 N sulfuric acid, and to the other add 2 mL of water: the solutions are equally clear after standing for 2 hours. 

Sodium ferrocyanide: Dissolve 25 g in 80 mL of water in a glass stoppered, 100-mL graduated cylinder or flask. Add 2 mL of ferrous sulfate TS and 1 mL of 2 N sulfuric acid, dilute with water to 100 mL, and mix. For a control, place 80 mL of water in a glass-stoppered, 100-mL graduated cylinder or flask, add 2 ml- of ferrous sulfate TS and 1 mL of 2 N sulfuric acid, dilute with water to 100 mL, and mix. Transfer 50-mL portions of the respective solutions to matched color-comparison tubes: the test solution shows no more blue color than the control, indicating the absence of sodium ferrocyanide.  

Sulfate: A 1.0 g portion shows no more sulfate than corresponds to 0.15 mL of 0.020 N sulfuric acid (0.015%). 

Heavy metals, Method 1: 5 ppm. 

Organic volatile impurities, Method IV: meets the requirements. 

Assay: Transfer about 250 mg of Sodium Chloride, accurately weighed, to a porcelain casserole, and add 140 mL of water and 1 mL of dichlorofluorescein TS. Mix, and titrate with 0.1 N silver nitrate VS until the silver chloride flocculates and the mixture acquires a faint pink color. Each mL of 0.1 N silver nitrate is equivalent to 5.844 mg of NaCl.