1. No category

Accessed from 10.6.1.1 by correct6 on Mon May 18 11:02:06 EDT 2015
NF 33
Official Monographs / Silicon 6863
IMPURITIES
Inorganic Impurities
• LOSS ON IGNITION 〈733〉
Sample: 1 g
Analysis: Ignite the Sample, previously dried and
weighed, at 1000° for NLT 1 h.
Acceptance criteria: It loses NMT 8.5% of its weight.
• CHLORIDE AND SULFATE, Chloride 〈221〉: Boil 5 g in 50 mL
of water under a reflux condenser for 2 h, cool, and
filter. A 7-mL portion of the filtrate shows no more chloride than corresponds to 1.0 mL of 0.020 N hydrochloric
acid (0.1%).
• CHLORIDE AND SULFATE, Sulfate 〈221〉: A 10-mL portion of
the filtrate from the test for Chloride shows no more sulfate than corresponds to 5.0 mL of 0.020 N sulfuric acid
(0.5%).
• ARSENIC, Method I 〈211〉
Sample solution: Transfer 4.0 g to a platinum dish.
Add 5 mL of nitric acid and 35 mL of hydrofluoric acid,
and evaporate on a steam bath. Cool. Add 5 mL of
perchloric acid, 10 mL of hydrofluoric acid, and 10 mL
of sulfuric acid, and evaporate on a hot plate to the
production of heavy fumes. Cool. Cautiously transfer to
a 100-mL beaker with the aid of a few mL of hydrochloric acid, and evaporate to dryness. Cool. Add 5 mL
of hydrochloric acid, dilute with water to 40 mL, and
heat to dissolve any residue. Cool. Transfer to a
100-mL volumetric flask, and dilute with water to
volume.
Analysis: Use a 25.0-mL portion of the Sample solution.
Acceptance criteria: Meets the requirements of the
test (NMT 3 ppm)
Delete the following:
•• HEAVY METALS, Method I 〈231〉
.
Sample solution: 16.7 mL of the solution prepared for
the test for Arsenic
Analysis: Transfer the Sample solution to a 100-mL
beaker, and neutralize to litmus paper with ammonium
hydroxide. Adjust with 6 N acetic acid to a pH between
3 and 4. Filter, using medium-speed filter paper, and
wash with water until the filtrate and washings measure
40 mL.
Acceptance criteria: NMT 30 ppm• (Official 1-Dec-2015)
SPECIFIC TESTS
• PH 〈791〉: 4–8 in a slurry (1 in 20)
• LOSS ON DRYING 〈731〉: Dry a sample at 145° for 4 h; it
loses NMT 5.0% of its weight.
.
Colloidal Silicon Dioxide
SiO2
Silica [7631-86-9].
60.08
DEFINITION
Colloidal Silicon Dioxide is a submicroscopic fumed silica
prepared by the vapor-phase hydrolysis of a silicon compound. When ignited at 1000° for 2 h, it contains NLT
99.0% and NMT 100.5% of SiO2.
ASSAY
• PROCEDURE
Sample: 500 mg
Analysis: Ignite the Sample in a tared platinum crucible
at 1000 ± 25° for 2 h, cool in a desiccator, and weigh.
Add 3 drops of sulfuric acid, and add enough alcohol to
just moisten the sample completely. Add 15 mL of hydrofluoric acid, and in a well-ventilated hood evaporate
on a hot plate to dryness, using medium heat
(95°–105°) and taking care that the sample does not
spatter as dryness is approached. Heat the crucible to a
red color with the aid of a Bunsen burner. Ignite the
residue at 1000 ± 25° for 30 min, cool in a desiccator,
and weigh. If a residue remains, repeat the Analysis, beginning with “Add 15 mL of hydrofluoric acid”. The
weight lost by the assay specimen, previously ignited at
1000 ± 25°, represents the weight of SiO2 in the portion
taken.
Acceptance criteria: 99.0%–100.5% on the previously
ignited basis
IMPURITIES
Inorganic Impurities
• LOSS ON IGNITION 〈733〉: Ignite the portion of Colloidal
Silicon Dioxide, retained from the test for Loss on Drying,
at 1000 ± 25° to constant weight: the previously dried
Colloidal Silicon Dioxide loses NMT 2.0% of its weight.
• ARSENIC, Method 1 〈211〉
Sample solution: To 2.5 g add 50 mL of 3 N hydrochloric acid, and reflux for 30 min using a water condenser. Cool, filter with the aid of suction, and transfer
the filtrate to a 100-mL volumetric flask. Wash the filter
and flask with several portions of hot water, and add
the washings to the flask. Cool, and dilute with water
to volume.
Analysis: A 15.0-mL portion of Sample solution, to
which 3 mL of hydrochloric acid has been added,
meets the requirements of the test, the addition of the
7 N sulfuric acid being omitted.
Acceptance criteria: NMT 8 ppm
SPECIFIC TESTS
• PH 〈791〉: 3.5–5.5, in a (1 in 25) dispersion
• LOSS ON DRYING 〈731〉: Dry in a tared platinum crucible
at 105° for 2 h: it loses NMT 2.5% of its weight. Retain
the dried specimen in the crucible for the test for Loss on
Ignition.
ADDITIONAL REQUIREMENTS
• PACKAGING AND STORAGE: Preserve in well-closed
containers.
Official from May 1, 2015
Copyright (c) 2015 The United States Pharmacopeial Convention. All rights reserved.
NF Monographs
ADDITIONAL REQUIREMENTS
• PACKAGING AND STORAGE: Preserve in tight containers,
protected from moisture.
• LABELING: Label it to state whether it is silica gel or precipitated silica.
IDENTIFICATION
• A. PROCEDURE
Analysis: Transfer 5 mg to a platinum crucible, and mix
with 200 mg of anhydrous potassium carbonate. Heat
the crucible to a red color with the aid of a Bunsen
burner for 10 min, and cool. Dissolve the melt in 2 mL
of freshly distilled water, warming if necessary, and
slowly add 2 mL of ammonium molybdate TS to the
solution.
Acceptance criteria: A deep yellow color is produced.
• B. PROCEDURE
[NOTE—Avoid contact with o-tolidine when performing
this test, and conduct the test in a well-ventilated
hood.]
Analysis: Place 1 drop of the yellow silicomolybdate solution from Identification test A on a filter paper, and
evaporate the solvent. Add 1 drop of a saturated solution of o-tolidine in glacial acetic acid to reduce the
silicomolybdate to molybdenum blue, and place the paper over ammonium hydroxide.
Acceptance criteria: A greenish blue spot is produced.
Accessed from 10.6.1.1 by correct6 on Mon May 18 11:02:06 EDT 2015
6864 Simethicone / Official Monographs
Simethicone—see Simethicone General
Monographs
Simethicone Emulsion—see Simethicone
Emulsion General Monographs
.
Soda Lime
DEFINITION
Soda Lime is a mixture of Calcium Hydroxide and Sodium
or Potassium Hydroxide or both. It may contain an indicator that is inert toward anesthetic gases such as Ether,
Cyclopropane, and Nitrous Oxide and that changes color
when the Soda Lime can no longer absorb Carbon
Dioxide.
NF Monographs
IDENTIFICATION
• A.
Analysis: Place a granule on a piece of moistened red
litmus paper.
Acceptance criteria: The paper turns blue immediately.
• B. IDENTIFICATION TESTS—GENERAL, Calcium 〈191〉
Sample solution: A solution in 6 N acetic acid
Acceptance criteria: Meets the requirements. It also
imparts a yellow color to a nonluminous flame that,
when viewed through cobalt glass, may show a violet
color.
SPECIFIC TESTS
• LOSS ON DRYING 〈731〉
Sample: 10 g
Analysis: Dry at 105° for 2 h.
Acceptance criteria: 12.0%–19.0%
• CARBON DIOXIDE ABSORBENCY
Analysis: Fill the lower transverse section of a U-shaped
drying tube of 15-mm internal diameter and 15-cm
height with loosely packed glass wool. In one arm of
the tube, place 5 g of anhydrous calcium chloride, and
weigh the tube and the contents. In the other arm,
place 9.5–10.5 g of Soda Lime, and again weigh. Insert
stoppers in the open arms of the tube, and connect the
side tube of the arm filled with Soda Lime to a calcium
chloride drying tube, which in turn is connected to a
suitable source of supply of carbon dioxide. Pass the
carbon dioxide through the tube at 75 mL/min for 20
min, accurately timed. Disconnect the tube, cool to
room temperature, remove the stoppers, and weigh.
Acceptance criteria: NLT 19.0% increase in weight of
the Soda Lime used for the test
• HARDNESS
Sample: 200 g
Analysis: Screen the Sample on a mechanical sieve
shaker (see Particle Size Distribution Estimation by Analytical Sieving 〈786〉) having a frequency of oscillation of
285 ± 3 cycles/min, for 3 min, to remove granules both
coarser and finer than the labeled particle size. Weigh
50 g of the granules retained on the screen, and place
them in a hardness pan that has a diameter of 200 mm
and a concave brass bottom 7.9 mm thick at the circumference and 3.2 mm thick at the center, with an
inside spherical radius of curvature of 109 cm. Add 15
steel balls of 7.9-mm diameter, and shake on a mechanical sieve shaker for 30 min. Remove the steel balls,
brush the contents of the hardness pan onto a sieve of
the fine-mesh size designated on the label, shake for 3
min on the mechanical sieve shaker, and weigh.
Acceptance criteria: NLT 75.0% of Soda Lime is retained on the screen.
NF 33
• MOISTURE ABSORPTION
Sample: 10 g
Analysis: Place the Sample in a tared 50-mL weighing
bottle having a diameter of 50 mm and a height of
30 mm, and weigh. Then place the bottle, with cover
removed, for 24 h in a closed container in which the
atmosphere is maintained at 85% relative humidity by
being in equilibrium with sulfuric acid having a specific
gravity of 1.16. Weigh again.
Acceptance criteria: The weight increase is NMT 7.5%.
• PARTICLE SIZE DISTRIBUTION ESTIMATION BY ANALYTICAL
SIEVING, Method I 〈786〉
Sample: 100 g
Analysis: Screen the Sample for 5 min as directed, using
a mechanical shaker.
Acceptance criteria: It passes completely through a
No. 2 standard-mesh sieve, and NMT 2.0% passes
through a No. 40 standard-mesh sieve. NMT 7.0% is
retained on the coarse-mesh sieve, and NMT 15.0%
passes through the fine-mesh sieve designated on the
label.
ADDITIONAL REQUIREMENTS
• PACKAGING AND STORAGE: Preserve in tight containers.
• LABELING: If an indicator has been added, the name and
color change of such indicator are stated on the container label. The container label also indicates the mesh
size in terms of standard-mesh sieve sizes (see Powder
Fineness 〈811〉).
Sodium Acetate—see Sodium Acetate
General Monographs
.
Sodium Alginate
(C6H7NaO6)n
Alginic acid, sodium salt;
Sodium alginate [9005-38-3].
DEFINITION
Sodium Alginate is the purified carbohydrate product extracted from brown seaweeds by the use of dilute alkali. It
consists chiefly of the sodium salt of Alginic Acid, a polyuronic acid composed of β-D-mannuronic acid residues
linked so that the carboxyl group of each unit is free
while the aldehyde group is shielded by a glycosidic linkage. It contains NLT 90.8% and NMT 106.0% of sodium
alginate of average equivalent weight 222.00, calculated
on the dried basis.
IDENTIFICATION
• A.
Sample solution: A solution (1 in 100)
Analysis: To 5 mL of Sample solution add 1 mL of calcium chloride TS.
Acceptance criteria: A voluminous, gelatinous precipitate is formed immediately.
• B.
Sample solution: A solution (1 in 100)
Analysis: To 10 mL of Sample solution add 1 mL of 4 N
sulfuric acid.
Official from May 1, 2015
Copyright (c) 2015 The United States Pharmacopeial Convention. All rights reserved.