» Resorcinol contains not less than 99.0 percent and not more than 100.5 percent of C6H6O2, calculated on the dried basis.
Packaging and storage Preserve in well-closed, light-resistant containers.
A: Infrared Absorption 197K[noteIf necessary to recrystallize, dissolve in dehydrated alcohol.]
B: Dissolve 100 mg in 2 mL of 1 N sodium hydroxide, add 1 drop of chloroform, and heat the mixture: an intense crimson color is produced. Then add a slight excess of hydrochloric acid: the color changes to pale yellow.
C: To 10 mL of a solution (1 in 100) add 1 drop of ferric chloride TS: a blue-violet color is produced, and it fades slowly.
Melting range 741: between 109 and 111.
Loss on drying 731 Dry it over silica gel for 4 hours: it loses not more than 1.0% of its weight.
Residue on ignition 281: not more than 0.05%.
Phenol Heat gently a solution (1 in 20): the odor of phenol is not perceptible.
Catechol To 10 mL of a solution (1 in 20) previously mixed with 2 drops of 1 N acetic acid add 0.5 mL of lead acetate TS: no turbidity is produced.
Ordinary impurities 466
Test solution: methanol.
Standard solution: methanol.
Eluant: a mixture of hexanes and ethyl acetate (70:30).
Visualization: 17 and then 1.
Application volume: 10 µL.
Limits: not more than 1.0%.
Assay Dissolve about 1.5 g of Resorcinol, accurately weighed, in water to make 500.0 mL. Transfer to an iodine flask 25.0 mL of the resulting solution, add 50.0 mL of 0.1 N bromine VS, dilute with 50 mL of water, add 5 mL of hydrochloric acid, and at once insert the stopper in the flask. Shake for 1 minute, allow to stand for 2 minutes, and add 10 mL of potassium iodide TS while slightly loosening the stopper. Shake thoroughly, allow to stand for 5 minutes, remove the stopper, and rinse it and the neck of the flask with 20 mL of water into the flask. Titrate the liberated iodine with 0.1 N sodium thiosulfate VS, adding starch TS as the endpoint is approached. Perform a blank determination. From the volume of 0.1 N sodium thiosulfate VS used, calculate the volume, in mL, of 0.1 N bromine VS consumed by the resorcinol. Each mL of 0.1 N bromine is equivalent to 1.835 mg of C6H6O2.
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USP32NF27 Page 3494
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.