» Oxybenzone contains not less than 97.0 percent and not more than 103.0 percent of C14H12O3, calculated on the dried basis.
Packaging and storage Preserve in tight, light-resistant containers.
USP Reference standards 11
USP Oxybenzone RS.
Solution: 10 µg per mL.
Absorptivities at 287 nm, calculated on the dried basis, do not differ by more than 3.0%.
Congealing temperature 651: not lower than 62.0.
Loss on drying 731 Dry it in vacuum at 40 for 2 hours: it loses not more than 2.0% of its weight.
Standard preparation Dissolve an accurately weighed quantity of USP Oxybenzone RS in methanol, and quantitatively dilute with methanol, if necessary, to obtain a solution having a known concentration of about 10 µg per mL.
Assay preparation Dissolve about 100 mg of Oxybenzone, accurately weighed, in methanol in a 100-mL volumetric flask, dilute with methanol to volume, and mix. Agitate gently, if necessary, to hasten solution. Pipet 1 mL of the solution so obtained into a second 100-mL volumetric flask, dilute with methanol to volume, and mix.
Procedure Concomitantly determine the absorbances of the Assay preparation and the Standard preparation in 1-cm cells at the wavelength of maximum absorbance at about 287 nm, with a suitable spectrophotometer, using methanol as the blank. Calculate the quantity, in mg, of C14H12O3 in the portion of Oxybenzone taken by the formula:
10C(AU / AS)in which C is the concentration, in µg per mL, of USP Oxybenzone RS in the Standard preparation; and AU and AS are the absorbances of the Assay preparation and the Standard preparation, respectively.
Auxiliary Information Please check for your question in the FAQs before contacting USP.Chromatographic Column
USP32NF27 Page 3160Pharmacopeial Forum: Volume No. 27(3) Page 2572
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.