Sodium Benzoate
(soe' dee um ben' zoe ate).
DEFINITION
Sodium Benzoate contains NLT 99.0% and NMT 100.5% of C7H5NaO2, calculated on the anhydrous basis.
IDENTIFICATION
• A. Infrared Absorption 197M:
On the undried specimen
• B. Identification TestsGeneral, Sodium 191:
Meets the requirements
• C. Identification TestsGeneral, Benzoate 191:
Meets the requirements
ASSAY
• Procedure
Sample:
600 mg
Titrimetric system
(See Titrimetry 541.)
Mode:
Direct titration
Titrant:
0.1 N perchloric acid VS
Blank:
100 mL of glacial acetic acid
Endpoint detection:
Visual
Analysis:
To the Sample add 100 mL of glacial acetic acid, and stir until completely dissolved. Add 2 drops of crystal violet TS, and titrate with 0.1 N perchloric acid VS to a green endpoint. Perform a blank determination.
Calculate the percentage of sodium benzoate (C7H5NaO2) in the Sample taken:
Result = [(VS VB) × N × F]/W × 100
Acceptance criteria:
99.0%100.5% on the anhydrous basis
IMPURITIES
• Heavy Metals 231
Test preparation:
4.0 g in 40 mL of water
Analysis:
To the Test preparation add dropwise with vigorous stirring 10 mL of 3 N hydrochloric acid, and filter. Use 25 mL of the filtrate.
Acceptance criteria:
NMT 10 ppm
SPECIFIC TESTS
• Water Determination, Method I 921:
NMT 1.5%
• Alkalinity
Sample solution:
2 g in 20 mL of hot water
Analysis:
To the Sample solution add 2 drops of phenolphthalein TS.
Acceptance criteria:
The pink color produced, if any, is discharged by the addition of 0.20 mL of 0.10 N sulfuric acid.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 1950
Pharmacopeial Forum: Volume No. 31(3) Page 818
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