» Dichlorotetrafluoroethane contains not less than 99.6 percent and not more than 100.0 percent of C2C12F4, calculated on the anhydrous basis.
Packaging and storage Preserve in tight cylinders, and avoid exposure to excessive heat.
Identification The IR absorption spectrum of it, determined in a 10-cm cell with sodium chloride windows, at atmospheric pressure, exhibits maxima, among others, at the following wavelengths, in µm: 4.34 (s), 4.48 (m), 5.28 (m), 5.95 (m), 7.36 (s), 9.5 (vs), 10.9 (vs), 11.8 (vs), 13.6 (s), and 14.8 (s). The stronger maxima are best obtained at pressures less than 10 mm of mercury.
Boiling temperature: approximately 4, determined as directed under Approximate Boiling Temperature (see Aerosols, Nasal Sprays, Metered-Dose Inhalers, and Dry Powder Inhalers 601).
Water: not more than 0.001%, determined as directed under Water Content (see Aerosols, Nasal Sprays, Metered-Dose Inhalers, and Dry Powder Inhalers 601).
High-boiling residues: not more than 0.01%, determined as directed for High-Boiling Residues, Method I, under Aerosols, Nasal Sprays, Metered-Dose Inhalers, and Dry Powder Inhalers 601.
Chromatographic purity In the chromatogram recorded for the Assay, identify the peaks due to dichlorodifluoromethane and trichloromonofluoromethane from relative retention times observed on chromatographing the Resolution preparation: the sum of these two peak areas is not greater than 0.2% of the total of all peak areas, and the sum of the areas of all peaks other than that for dichlorotetrafluoroethane is not greater than 0.4% of the total of all peak areas.
Inorganic chlorides Place 5 mL of anhydrous methanol in a test tube, add 3 drops of a saturated solution of silver nitrate in anhydrous methanol, shake, and add 7 g of Dichlorotetrafluoroethane: no opalescence or turbidity is produced.
Resolution preparation and Chromatographic systemProceed as directed in the Assay under Dichlorodifluoromethane.
Assay preparation Introduce the liquid phase of Dichlorotetrafluoroethane into an evacuated headspace vial.
Procedure Inject the gas phase headspace Assay preparation into the chromatograph, record the chromatogram, and measure the peak areas. Calculate the percentage (a/a) of C2C12F4 in the portion of Dichlorotetrafluoroethane taken.
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USP32NF27 Page 1225
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.