Melting range 741 : between 37 and 39.

Assay— When tested by thin-layer chromatography (see Chromatography 621) with the use of plates coated with chromatographic silica gel mixture and a developing system consisting of a mixture of toluene and ethanol (9:1), examined under short-wavelength UV light, a single spot is exhibited, with trace impurities.

Melting range 741: between 172 and 177.

Melting range, Class II 741 : between 256 and 260.

Specific rotation 781 : between +85 and +88, determined in a solution in dioxane containing 75 mg of equilenin in each 10 mL.

Absorption maxima— An alcohol solution exhibits absorption maxima at 231, 282, 325, and 340 nm.

Solubility— 200 mg in 100 mL of water yields a solution that remains clear and free from undissolved matter for 30 minutes.

Loss on drying 731— Dry it in vacuum over silica gel to constant weight: it loses not more than 2% of its weight.

Residue on ignition (Reagent test)— 0.5 g, treated with 1 mL of sulfuric acid and 2 mL of nitric acid, yields between 42.0% and 44.0% of the dry weight (theoretical yield is 42.9% of Na2SO4).

Sensitiveness— Add 2 mL of a solution (1 in 1000) to 1 mL of aluminum sulfate solution (1 in 10,000), heat at 37 ± 3 for 5 minutes, cool, and add 1 mL of sodium acetate TS: a strong red to red-violet color is produced in not more than 5 minutes.

Assay— Accurately weigh about 300 mg, dissolve in 30 mL of water, add phenolphthalein TS, and titrate with 0.1 N sodium hydroxide VS. Each mL of 0.1 N sodium hydroxide is equivalent to 11.013 mg of C2H5SO3H: between 94.0% and 106.0% is found.

Refractive index 831: between 1.432 and 1.436 at 20.

Peroxide— Transfer 8 mL of potassium iodide and starch TS to a 12-mL ground glass-stoppered cylinder about 15 mm in diameter. Fill completely with the substance under test, mix, and allow to stand protected from light for 5 minutes. No color develops. Alternatively, peroxide test strips may be used.

Specific gravity 841 : about 0.93.

Boiling range (Reagent test)— Not less than 95% distills between 133 and 135.

Assay— Dissolve about 50 mg in 1 mL of ether. Inject about 1 µL of this solution into a suitable gas chromatograph (see Chromatography 621) equipped with a flame-ionization detector and a 0.25-mm × 30-m capillary column containing stationary phase G1. The carrier gas is helium. The chromatograph is programmed as follows. Initially, the column temperature is equilibrated at 180, then the temperature is increased at a rate of 10 per minute to 280, and maintained at 280 for 10 minutes. The injection port temperature is maintained at 280, and the detector is maintained at 300. The area of the 4¢-ethoxyacetophenone peak is not less than 97.5% of the total peak area.

Melting range 741: between 34 and 39.

Assay— Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography 621), helium being used as the carrier gas. The following conditions have been found suitable: a 3-mm × 2.4-m stainless steel column containing 20% phase G16 on support S1A; the injection port, column, and detector temperatures are maintained at 180, 195, and 250, respectively. The area of the ethyl benzoate peak is not less than 98% of the total peak area.

Refractive index 831: between 1.5048 and 1.5058 at 20.

Specific gravity 841 : between 1.057 and 1.062.

Acidity— Dissolve 2 mL in 25 mL of neutralized alcohol, add phenolphthalein TS, and titrate with 0.10 N sodium hydroxide: not more than 1.5 mL is required to produce a pink color.

Assay— Transfer about 80 mg, accurately weighed, to a suitable beaker, add 30 mL of methanol, and dissolve by stirring. Slowly add 40 mL of deionized water. [note—If cloudiness appears when adding the deionized water, dissolve in 50 mL of methanol only.] When solution is complete, titrate with 0.1 N sodium hydroxide VS, determining the endpoint potentiometrically. Perform a blank titration, and make any necessary correction. Each mL of 0.1 N sodium hydroxide is equivalent to 16.02 mg of C7H12O4. Not less than 98.5% of C7H12O4 is found.

Melting point 741: between 101 and 103.

Assay— Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography 621) equipped with a flame-ionization detector, helium being used as the carrier gas. The following conditions have been found suitable: a 0.25-mm × 10-m capillary column coated with a 1-µm layer of methylsilicone; the injection port temperature is maintained at 240; the detector temperature is maintained at 300; the column temperature is maintained at 150 and programmed to rise 10 per minute to 250. The area of the ethyl salicylate peak is not less than 99% of the total peak area.

Refractive index 831: between 1.5216 and 1.5236 at 20.

Assay— Dissolve about 600 mg, accurately weighed, in a mixture of 100 mL of alcohol and 25 mL of 1 M hydroxylamine hydrochloride in a beaker. Cover the beaker with a watch glass. Heat gently until condensate begins to form on the watch glass. Allow to cool for about 30 minutes. Titrate with 0.5 N sodium hydroxide VS, determining the endpoint potentiometrically. Perform a blank determination, and make any necessary correction. Each mL of 0.5 N sodium hydroxide is equivalent to 67.09 mg of C2H5C6H4CHO. Not less than 98% is found.

Specific gravity 841: about 1.11.

Boiling range (Reagent test): between 194 and 200.

Residue on ignition— Evaporate 100 mL (110 g) in a tared evaporating dish over a flame until the vapors continue to burn after the flame is removed. Allow the vapors to burn until the specimen is consumed. Ignite at 800 ± 25 for 1 hour, cool, and weigh: the residue weighs not more than 5.5 mg (0.005%).

Acidity— Add 0.2 mL of phenol red TS to 50 mL of water, and titrate with 0.1 N sodium hydroxide to a red endpoint. Add 50 mL (55 g) of ethylene glycol, and titrate with 0.1 N sodium hydroxide: not more than 1 mL is required to restore the red color (0.01% as CH3COOH).

Chloride (Reagent test)— A 4.5-mL (5-g) portion shows not more than 0.025 mg of Cl (5 ppm).

Water, Method I 921: not more than 0.20%.

Melting range 741: between 43 and 47.

Assay— Dissolve about 290 mg, accurately weighed, in 100 mL of water, and add 10 mL of glacial acetic acid. Titrate with 0.1 N silver nitrate VS, determining the endpoint potentiometrically, using a silver-ion selective electrode and a calomel reference electrode containing 1 M potassium nitrate. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N silver nitrate is equivalent to 29.92 mg of C12H14IN: not less than 97.0% is found.