Sodium Borate
Na2B4O7·10H2O 381.37
Na2B4O7 201.22
Borax
[1303-96-4].
Anhydrous[1330-43-4].
(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 Tests—General, Sodium 
191
191
Sample solution:
1 in 20
Acceptance criteria:
Meets the requirements
• B. Identification Tests—General, Borate 191
191
Sample solution:
1 in 20
Acceptance criteria:
Meets the requirements
ASSAY
• Procedure
Sample:
3 g of Sodium Borate
Titrimetric system
(See Titrimetry 541.)
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. [Note—Heating 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
B) × N × F] × 100/W
| V | = | = volume of Titrant consumed by the Sample (mL) |
| B | = | = volume of Titrant consumed by the Blank (mL) |
| N | = | = actual normality of the Titrant (mEq/mL) |
| F | = | = equivalency factor, 190.7 mg/mEq |
| W | = | = weight of the Sample (mg) |
Acceptance criteria:
99.0%–105.0%
IMPURITIES
• Heavy Metals 231
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—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Robert H. Lafaver, M.S.
Scientific Liaison 1-301-816-8335 |
(EXC2010) Monographs - Excipients |
USP35–NF30 Page 1951