Sodium Borate
Na2B4O7·10H2O 381.37

Borax [1303-96-4].

Anhydrous 201.22 [1330-43-4].
» Sodium Borate contains an amount of Na2B4O7 equivalent to not less than 99.0 percent and not more than 105.0 percent of Na2B4O7·10H2O.
Packaging and storage— Preserve in tight containers.
Identification— A solution (1 in 20) responds to the tests for Sodium 191 and for Borate 191.
Carbonate and bicarbonate— To 5 mL of a solution (1 in 20), contained in a test tube, add 1 mL of 3 N hydrochloric acid: no effervescence is observed.
Heavy metals 231 Dissolve 1 g in 16 mL of water and 6 mL of 1 N hydrochloric acid, and dilute with water to 25 mL: the limit is 0.002%.
Assay— Dissolve about 3 g of Sodium Borate, accurately weighed, 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.] Each mL of 0.5 N hydrochloric acid is equivalent to 95.34 mg of Na2B4O7·10H2O.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, B.A.
(EM105) Excipient Monographs 1
USP32–NF27 Page 1340
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.