Sodium Chloride
Salt

NaCl Mol wt 58.44

DESCRIPTION

Salt is a generic term applied to commercially produced sodium
chloride, It is available in various crystalline forms, referred to
as evaporated salt, rock salt, solar salt, or simply salt. It may
contain up to 2% (total) of suitable food-grade anticaking, free-
flowing, or conditioning agents, either singly or in combination.
Tt may contain not more than 13 ppm of sodium ferrocyanide,
‘or not more than 25 ppm of green ferric ammonium citrate as
corystal-modifying and anticaking agents. If labeled as iodized, it
contains not less than 0.006% and not more than 0.010% of
potassium iodide,

Sodium chioride is a transparent to opaque, white crystalline
solid of variable particle size, (Rock salt may be white to off-
white ia color.) It remains dry in air at a relative humidity
below 75%, but becomes deliquescent at higher humidities. One
gis soluble in 2,8 mj of water at 25°, in 2.7 ml of boiling water.
and in about 10 ml of glycerin. Sodium chloride containing
water-insoluble anticaking, free-flowing, and conditioning
agents may produce cloudy solutions, or may dissolve incom-
pletely. A 1 in 20 solution usually has a pH between 5.5 and 8.5
(the pH may be higher if alkaline conditioning agents have been
added).

REQUIREMENTS

Identification

It gives positive tests for Sodium, page 917, and for Chloride,
page 516.

Assay
Evaporated salt with up to 2% of suitable free-Rowing or
conditioning agents and anticaking agents such as sodium
ferrocyanide: Not less than 97.5% of NaCl after drying at
625° for Zh.

Evaporated salt with only anticaking agents such as
sodium ferrocyanide: Not less than 99.0% after drying at
625° for 2h.

Rock or solar salt: Not less than 97.5% of NaCl after
drying at 625° for 2 h, the remainder consisting chichly of
minor amounts of naturally occurring components such as
alkaline and/or alkalinc earth sulfates and chlorides.

PAGE @1/

‘Arsenic (as As) Not more than 1 pro.

Calcium and Magnesium Not more than 2%.

‘Heavy Metals (as Pb) Not more than 4 ppm.

Todine Not less than 0.006% and not more than 0.010% of
potassium iodide. (NOTE: This specification applies only to
iodized salt.)

Tron Not more than 0.0016% of Fe, (NOTE: This specification
applies only to products to which green ferric ammonium
citrate has been added.)

‘Loss on Drying Not more than 0.5%.

Sodium Ferrocyanide Not more than 0.0013% of anhydrous
NaFe(CN),. (NOTE: This specification epplies only to
products to which sodium ferrocyanide has been added.)

TESTS

NOTE: In the following procedures, it may be necessary to
filter the sample solutions to avoid interference by insolu-
ble or suspended anticaking, free-flowing, or conditioning,
agents,

Assay Weigh accurately about 250 mg of the sample, previ-
ously dried at 625° for 2 h, and dissolve it in 50 ml of water in
a glass-stoppered flask. Add, while agitating, 3 mil of nitric
acid, S mi of nitrobenzene, 50,0 ml of 0.1 N silver nitrate, and
2 ml of ferric ammonium sulfate TS. Shake well, and titrate
the excess silver nitrate with 0.1 NV ammonium thiocyanate.
Each ml of 0.1 W silver nitrate is equivalent to 5,844 mg of
NaCl.

Arsenic A solution of 3 g of the sample in 25 ml of water
meets the requirements of the Arsenic Test, page 464.

Calcium and Magnestum

Standard EDTA Solution Dissolve 4.0 g of disodium
EDTA, CyoH,,NzNa,0,2H,0, in sufficient water to make

1000 mi.

Magnesium Sulfate Solution Dissolve 2.6 g of magncsium
sulfate, MgSO,7H,0, in sufficient water to make 1000 ml.

Buffer Solution (a) Initial Preparation: Transfer 67.5 g of
ammonivm chloride into « 1000-m! volumetric flask, and
dissolve in 570 ml of concentrated ammonium hydroxide.
Use 2 ml of this solution as directed below under Titer
Determination. (b) Final preparation: Pipet 50.0 mi of
Magnesium Sulfate Solution into the flask, add exactly the
volume T, in ml, of Standard EDTA Solution, determincd 6s
directed below under Titer Determination, then dilute to
volume with water, and mix,

Titer Determination Pipet 50.0 ml of Magnesium Sulfare
Solution into a 400-mi beaker, and add 200 ml of water, 2 ml
of Buffer Solution (initial preparation), 1.0 ml of potassium
cyanide solution (1 in 20), and 5 drops of eriochrome black
TS or other suitable indicator. Titrate with the Standard
EDTA Solution, while stirring with a magnetic stirrer, to a
true blue endpoint. Record the volume 7, in ml, of Standard
EDTA Solution equivalent to 50.0 ml of the Magnesium
Sulfate Solution.

Standardization of EDTA Solution Transfer about 1 g,
accurately weighed, of primary standard calcium carbonate,
CaCO,, into a 1000-ml volumetric flask, dissolve in 800 ml of
water containing 5 ml of concentrated hydrochloric acid,


dilute to volume with water, and mix. Pipet 25.0 mi of this
solution into a 400-ml beaker, and add 200 mi of water, 2 ml
of Buffer Solution (final preparation), 1.0 ml of potassium
cyanide solution (1 in 20), and 20 drops of criochrome black
TS of other suitable indicator. Titeate with the Standard
EDTA Solution, stirring with 2 magnetic stierer, to a true blue
endpoint. Calculate the factor F, giving the number of mg of
Ca equivalent to 1.0 mi of Standard EDTA Solution, by the
formula 10.011/», in which w is the exact weight, in g, of
the primary standard calcium carbonate taken, and v is the
yolume, in ml, of the Srandard EDTA Solution required in
the titration.

Sample Preparation for Rock and Solar Salt Transfer
$0.0 g of the sample into a 500-ml volumetric flask, dissolve
in 400 ml of water containing 2 ml of concentrated hydro-
chloric acid, dilute to volume with water, and mix. Filter a
$0-ml aliquot, then pipet 10.0 mi of the filtrate into a 400-ml
beaker, and add 190 mi of water.

Sample Preparation for Evaporated Salt Transfer 10.0 g
of the sample into a 400-mi beaker, and dissolve in 100 ml of
water. If free-flowing agents are present, filter and rinse
quantitatively. Dilute the solution or filtrate to 200 ml with
water.

Procedure To the Sample Preparation add 5 ml of Buffer
Solution (final preparation), 1 ml of potassium cyanide
solution (1 in 20), and 5 drops of criochrome black TS or
other suitable indicator. Begin stirsing with a magnetic
stirrer, and titrate with Seondord EDTA Solution to a true
Dlue endpoint, recording the volume, in mi, required as V.
Calculate the ppm of total calcium and magnesium (both
expressed as Ca) in the sample by the formula

vx FX 1000/4,

in which W is the weight, in g. of salt sample in the final
solution titrated.

Heavy Metals A solution of 5 g of the sample in 25 ml of
‘water mects the requirements of the Heavy Metals Test, page

$12, using 20 jug of lead ion (Pb) in the control (Solution A).

Jodine Transfer about 20 g of the sample, accurately weighed,
into a 600-mal beaker, and dissolve in about 300 ml of water.
Add a few drops of methyl orange TS, neutralize the solution
with phosphoric acid (85%), and then add 1 ml excess of the
acid. Add 25 ml of bromine TS and a few glass beads, boil
until the solution is clear, then boil for an additional $ min.
Add about 50 mg of salicylic acid crystals, 1 ml of phosphoric
acid, and 10 ml of potassium iodide solution (1 in 20), and
titrate to a pale yellow color with 0.01 V sodium thiosulfate.
Add 1 ml of starch TS, and continue the titration to the
disappearance of the blue color. Each mi! of 0.01 N sodium.
thiosulfate is equivalent to 0.2767 mg of KI.

Tron Dissolve 625.0 mg of the sample in 10 ml of diluted
hydrochloric acid TS, and dilute to 50 ml with water. Add
about 40 mg of ammonium persulfate crystals and 10 m! of

ammonium thiocyanate TS. Any red or pink color does not
exceed that produced by 1.0 ml of fron Standard Solution (10
ve Fe) in an equal volume of solution containing 2 ml of
hydrochloric acid and the quantities of ammonium persulfate
and ammonium thiocyanate used in thc test.

‘Loss on Drying, page 518 Dry at 110° for 2h.

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Fcc Hu / Monographs { 283

Sodium Ferrocyanide Dissolve 9.62 g of the sample in 80 jn)
of water in a 150-ml glass-stoppered cylinder or flask.
Prepare a standard solution containing 125 pg of
Na,Fe(CN), in each mi by dissolving 99.5 mg of
NaFe(CN)¢.10H,0 in $00.0 ml of water. then transfer 1.0 ml
of this solution into a similar 150-ml container for the
control. To each container add 2 mil of ferrous sulfate TS and
1 ml of diluted sulfuric acid TS, dilute to 100 onl with watcr,
and mix. Transfer $0-ml portions of the respective solutions
into matched color-comparison tubes. The sample solution
shows no more blue color than the control.

Packaging and Storage Store in.well-closcd containers.

Labeling Label the product to indicate whether or not it is
iodized.

Functional Use in Foods Nutrient; preservative; flavoring
agent and intensifier; curing agent; dough conditioner.