(eth klor' vi nol).
» Ethchlorvynol contains not less than 98.0 percent and not more than 100.0 percent of E-ethchlorvynol (C7H9ClO), calculated on the anhydrous basis.
Packaging and storage Preserve in tight, light-resistant glass or polyethylene containers, using polyethylene-lined closures.
USP Reference standards 11
B: Dissolve about 1 g in 20 mL of methanol. To 1 mL of the solution, add about 4 drops of 6 N ammonium hydroxide, mix, then add silver nitrate TS, a few drops at a time: a yellowish white precipitate is formed, and it at first redissolves, but becomes insoluble when an excess of silver nitrate TS has been added.
C: To 10 mL of the solution prepared in Identification test B add 5 mL of freshly prepared m-phenylenediamine hydrochloride-oxalic acid solution (prepared by dissolving 1 g of m-phenylenediamine hydrochloride and 1 g of oxalic acid in 35 mL of water and filtering, if necessary): a reddish orange color is produced in about 3 minutes.
Refractive index 831: between 1.476 and 1.480.
Acidity Dissolve 5.0 mL of Ethchlorvynol in 50 mL of a mixture of equal volumes of water and methanol that has been neutralized to the phenolphthalein endpoint with 0.1 N sodium hydroxide. Add 1 mL of phenolphthalein TS, and titrate with 0.10 N sodium hydroxide to a pink endpoint: not more than 1.7 mL of 0.10 N sodium hydroxide is required for neutralization.
Water, Method I 921: not more than 0.2%.
Chromatographic purity Calculate the percentage of each peak, other than the E-ethchlorvynol peak, observed in the chromatogram of the Ethchlorvynol obtained as directed in the Assay taken by the same formula:
100ri / rtin which ri is the response of each secondary peak and rt is the sum of all of the peaks observed in the chromatogram: not more than 0.2% of toluene, not more than 1.5% of Z-ethchlorvynol, and not more than 0.3% of any other impurity is found, and the total of all observed impurities is not more than 2.0%.
Resolution solution Add 2.5 µL of toluene to 0.5 mL of USP Ethchlorvynol RS, and mix.
Chromatographic system (see Chromatography 621)The gas chromatograph is equipped with a thermal conductivity detector and a 1.8-m × 4-mm glass column (pretreated with 10% dimethyldichlorosilane in toluene) packed with 10% phase G16 on 60- to 80-mesh support S1AB. The column is maintained at about 160, and the injector and the detector are maintained at about 200. The carrier gas is dry helium, flowing at a rate of about 30 mL per minute. Chromatograph the Resolution solution, and record the peak responses as directed for Procedure: the relative retention times for toluene, -chlorovinylethyl ketone (if present), Z-ethchlorvynol, and E-ethchlorvynol are about 0.1, 0.2, 0.8, and 1.0, respectively; the resolution, R, between the Z- and E-ethchlorvynol peaks is not less than 1.0; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure [noteUse peak areas where peak responses are indicated. ] Inject about 3 µL of Ethchlorvynol into the chromatograph, record the chromatogram, and measure the responses for all of the peaks. Calculate the percentage of E-ethchlorvynol (C7H9ClO) in the specimen of Ethchlorvynol taken by the formula:
100re / rtin which re is the response of the E-ethchlorvynol peak obtained in the chromatogram of the Ethchlorvynol and rt is the sum of the responses of all of the peaks observed in the chromatogram.
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