Beta Carotene
,-Carotene. all-trans--Carotene. (all-E)-1,1¢-(3,7,12,16-Tetramethyl-1,3,5,7,9,11,13,15,17-octadecanonaene-1,18-diyl)bis[2,6,6-trimethylcyclohexene] [7235-40-7]. » Beta Carotene contains not less than 96.0 percent and not more than 101.0 percent of C40H56.
Packaging and storage
Preserve in tight, light-resistant containers.
Identification
A:
Determine the absorbances of Assay preparation B at 455 nm and at 483 nm: the ratio of the absorbance at 455 nm to that at 483 nm is between 1.14 and 1.18.
B:
Determine the absorbance of Assay preparation B at 455 nm and that of Assay preparation A at 340 nm: the ratio of the absorbance at 455 nm to that at 340 nm is not less than 1.5.
Melting range 741:
between 176 and 182, with decomposition.
Loss on drying 731
Dry it in vacuum over phosphorus pentoxide at 40 for 4 hours: it loses not more than 0.2% of its weight.
Residue on ignition 281:
not more than 0.2%, 2 g of specimen being used.
Heavy metals, Method II 231:
0.001%.
Assay
[notePerform this procedure in subdued light, using low-actinic glassware.]
Assay preparation A
Transfer about 50 mg of Beta Carotene, accurately weighed, to a 100-mL volumetric flask, dissolve in 10 mL of acid-free chloroform, dilute with cyclohexane to volume, and mix. Pipet 5 mL of this solution into a 100-mL volumetric flask, dilute with cyclohexane to volume, and mix.
Assay preparation B
Pipet 5 mL of Assay preparation A into a 50-mL volumetric flask, dilute with cyclohexane to volume, and mix.
Procedure
Determine the absorbance of Assay preparation B, at the wavelength of maximum absorbance at about 455 nm, with a suitable spectrophotometer, using cyclohexane as the blank. Calculate the quantity, in mg, of C40H56 in the portion of Beta Carotene taken by the formula:
20,000 AX / 250
in which AX is the absorbance of Assay preparation B; and 250 is the absorptivity of pure beta carotene.
Auxiliary Information
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Chromatographic Column
USP32NF27 Page 1654
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.
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