Precipitated Sulfur
S 32.07
Sulfur
[7704-34-9].
S 32.07
Sulfur
[7704-34-9].DEFINITION
Precipitated Sulfur contains NLT 99.5% and NMT 100.5% of sulfur (S), calculated on the anhydrous basis.
IDENTIFICATION
• A.
It burns in the air to sulfur dioxide, which can be recognized by its characteristic odor.
ASSAY
• Procedure
Sample:
60 mg of Precipitated Sulfur
Titrimetric system
Mode:
Direct titration
Titrant:
0.1 N sodium hydroxide VS
Endpoint detection:
Visual
Analysis:
Proceed as directed in Oxygen Flask Combustion 
471
, using a 1000-mL flask and using a mixture of 10 mL of water and 5.0 mL of hydrogen peroxide TS as the absorbing liquid. When the combustion is complete, fill the lip of the flask with water; loosen the stopper; then rinse the stopper, the sample holder, and the sides of the flask with water; and remove the stopper assembly. Heat the contents of the flask to boiling, and boil for 2 min. Cool to room temperature, add phenolphthalein TS, and titrate with Titrant. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N sodium hydroxide is equivalent to 1.603 mg of sulfur (S).
471, using a 1000-mL flask and using a mixture of 10 mL of water and 5.0 mL of hydrogen peroxide TS as the absorbing liquid. When the combustion is complete, fill the lip of the flask with water; loosen the stopper; then rinse the stopper, the sample holder, and the sides of the flask with water; and remove the stopper assembly. Heat the contents of the flask to boiling, and boil for 2 min. Cool to room temperature, add phenolphthalein TS, and titrate with Titrant. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N sodium hydroxide is equivalent to 1.603 mg of sulfur (S).
Acceptance criteria:
99.5%–100.5% on the anhydrous basis
OTHER COMPONENTS
• Other Forms of Sulfur
Sample:
1.0 g
Analysis:
Shake the Sample with 5 mL of carbon disulfide.
Acceptance criteria:
It dissolves quickly, with the exception of a small quantity of insoluble matter that is usually present.
IMPURITIES
• Residue on Ignition 281:
NMT 0.3%
281:
NMT 0.3%
SPECIFIC TESTS
• Water Determination, Method I 921:
NMT 0.5%
921:
NMT 0.5%
• Reaction
Sample:
2.0 g
Analysis:
Agitate the Sample with 10 mL of water, and filter.
Acceptance criteria:
The filtrate is neutral to litmus.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Alan R Potts, PhD
Principal Scientific Liaison (301) 816-8364 |
(SM12010) Monographs - Small Molecules 1 |
USP38–NF33 Page 5408