Sodium Borate
(soe' dee um bore' ate).
Na2B4O7·10H2O 381.37 Na2B4O7 201.22 Borax [1303-96-4]. Anhydrous [1330-43-4]. DEFINITION
Sodium Borate contains an amount of Na2B4O7 equivalent to NLT 99.0% and NMT 105.0% of Na2B4O7·10H2O.
IDENTIFICATION
• A. Identification TestsGeneral, Sodium 191
Sample solution:
1 in 20
Acceptance criteria:
Meets the requirements
• B. Identification TestsGeneral, Borate 191
Sample solution:
1 in 20
Acceptance criteria:
Meets the requirements
ASSAY
• Procedure
Sample:
3 g of Sodium Borate
Titrimetric system
(See Titrimetry 541.)
Mode:
Direct titration
Titrant:
0.5 N hydrochloric acid VS
Blank:
50 mL of water
Endpoint detection:
Visual
Analysis:
Dissolve the Sample in 50 mL of water, add methyl red TS, and titrate with 0.5 N hydrochloric acid VS. [NoteHeating on a steam bath may be required initially to effect solution. ]
Calculate the percentage of sodium borate (Na2B4O7·10H2O) in the Sample taken:
Result = [(V B) × N × F] × 100/W
Acceptance criteria:
99.0%105.0%
IMPURITIES
• Heavy Metals 231
Test preparation:
Dissolve 1 g in 16 mL of water and 6 mL of 1 N hydrochloric acid. Dilute with water to 25 mL.
Acceptance criteria:
NMT 20 ppm
• Carbonate and Bicarbonate
Sample solution:
To 5 mL of a solution (1 in 20), contained in a test tube, add 1 mL of 3 N hydrochloric acid.
Acceptance criteria:
No effervescence is observed.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in tight containers.
Auxiliary Information
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USP35NF30 Page 1951
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