Melting range 741: between 114 and 116.

Reaction— Its saturated solution is neutral to litmus.

Loss on drying 731— Dry it over sulfuric acid for 2 hours: it loses not more than 0.5% of its weight.

Residue on ignition (Reagent test): not more than 0.05%.

Change to read:

Residue on evaporation— Evaporate 50 mL on a steam bath, and dry the residue at 105 for 2 hours: the residue weighs not more than 1 mg (0.002%).

Chloride (Reagent test)— Five mL shows not more than 0.01 mg of Cl (2 ppm).

Sulfate (Reagent test, Method I )— Ten mL shows not more than 0.5 mg of SO4 (50 ppm).

Heavy metals (Reagent test)— Evaporate 20 mL on a steam bath to dryness. Add to the residue 2 mL of the acid, dilute with water to 25 mL, and add 10 mL of hydrogen sulfide TS: any brown color produced is not darker than that of a control containing 0.04 mg of added Pb and 2 mL of the diluted acetic acid (2 ppm).

Spectral purity— Measure in a 1-cm cell between 250 nm and 280 nm, with a suitable spectrophotometer, against air as the blank: its absorbance is not more than 0.01.

Melting range 741 : between 19 and 20.

Refractive index 831 : about 1.534 at 20.

Specific gravity 841 : about 1.03.

Assay— Inject an appropriate volume into a 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 230; the detector temperature is maintained at 300; and the column temperature is maintained at 130 and programmed to rise 10 per minute to 280. The area of the C9H11NO peak is not less than 98.5% of the total peak area.

Melting range 741: between 145 and 151.

Assay— Not less than 98% of C5H8O2, a suitable gas chromatograph equipped with a flame-ionization detector being used and helium being used as the carrier gas. The following conditions have been found suitable: a 3-mm × 1.83-m stainless steel column containing 10% phase G on support S1A; the injection port and detector temperatures are maintained at 250 and 310, respectively; the column temperature is programmed to rise 8 per minute, from 50 to 220.

Refractive index 831: between 1.4505 and 1.4525, at 20.

Specific gravity 841: about 1.1.

Melting range 741— When previously dried at 110 in a capillary tube for 1 hour, it melts between 149 and 152.

Reaction— A solution (1 in 10) is neutral to litmus.

Residue on ignition (Reagent test): negligible, from 200 mg.

Solubility in alcohol— A solution of 500 mg in 5 mL of alcohol is complete and colorless.

Percent of acetyl (CH3CO)— Weigh accurately about 400 mg, previously dried at 105 for 3 hours, and dissolve in 15 mL of water in a glass-stoppered conical flask. Add 40.0 mL of 0.1 N sodium hydroxide VS, and heat on a steam bath for 30 minutes. Insert the stopper, allow to cool, add phenolphthalein TS, and titrate the excess alkali with 0.1 N sulfuric acid VS. Determine the exact normality of the 0.1 N sodium hydroxide by titrating 40.0 mL after it has been treated in the same manner as in the test. Each mL of 0.1 N sodium hydroxide is equivalent to 4.305 mg of CH3CO. Between 23.2% and 24.2% is found.

Percent of chlorine (Cl)— Weigh accurately about 400 mg, previously dried at 105 for 3 hours, and dissolve in 50 mL of water in a glass-stoppered, 125-mL flask. Add with agitation 30.0 mL of 0.1 N silver nitrate VS, then add 5 mL of nitric acid and 5 mL of nitrobenzene, shake, add 2 mL of ferric ammonium sulfate TS, and titrate the excess silver nitrate with 0.1 N ammonium thiocyanate VS: each mL of 0.1 N silver nitrate is equivalent to 3.545 mg of Cl. Between 19.3% and 19.8% of Cl is found.

Assay— Inject an appropriate specimen into a 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 × 30-m capillary column coated with a 1-µm layer of phase G2; the injection port temperature is maintained at 150; the detector temperature is maintained at 300; and the column temperature is maintained at 50 and programmed to rise 10 per minute to 200. The area of the C3H4O2 peak is not less than 99% of the total peak area.

Refractive index 831: between 1.419 and 1.423 at 20.

Melting range 741: between 270 and 271.

Residue on ignition (Reagent test): negligible, from 100 mg.

Water— Dry it at 105 to constant weight: it loses not more than 10.0% of its weight.

Assay— Weigh accurately about 0.3 g, and dissolve in 50 mL of alcohol. Add 25 mL of water, mix, and titrate with 0.5 N sodium hydroxide VS to a pH of 9.5. Perform a blank determination, and make any necessary correction. Each mL of 0.5 N sodium hydroxide is equivalent to 36.54 mg of C6H10O4. Not less than 98% is found.

Melting range 741 : between 151 and 155, but the range between beginning and end of melting does not exceed 2.

		Relative Proportions
Percent by Volume of C2H5OH at 15.56	Specific Gravity at 25	Alcohol, mL	Water, mL	Volume in mL of Alcohol, 94.9% v/v, Required for 100 mL
70	0.884	38.6	15	73.7
80	0.857	45.5	9.5	84.3
90	0.827	51	3	94.8

[94.9(d / c) 0.8096]100

Assay— Transfer about 20 mg, accurately weighed, to a 200-mL volumetric flask, dissolve in 1 mL of water, dilute with an ice-cold solution of bovine serum albumin (1 in 100) to volume, and mix. Use this solution as the Assay preparation. Dissolve 3.3 g of potassium pyrophosphate, 15 mg of dithiothreitol, and 40 mg of edetate disodium in 70 mL of water, adjust with citric acid monohydrate solution (2.1 in 10) to a pH of 9.0 ± 0.1, dilute with water to 100 mL, and mix to obtain a pH 9.0 buffer. Dissolve an accurately weighed quantity of -nicotinamide adenine dinucleotide (-NAD) in water to obtain a -NAD solution \ having a known concentration of about 20 mg per mL. Pipet 0.1 mL of the Assay preparation into a 1-cm spectrophotometric cell. Pipet 0.1 mL of water into a second 1-cm spectrophotometric cell to provide the reagent blank. Add 2.5 mL of pH 9.0 buffer, 0.2 mL of -NAD solution, and 0.1 mL of pyrazole solution (0.68 in 100) to each cell, and mix. Stopper the cells, and allow to stand for 2 minutes at 25 ± 1. Add 0.01 mL of acetaldehyde solution (0.3 in 100) to each cell, and mix. Stopper the cells, and determine the absorbance of the solution obtained from the Assay preparation at a wavelength of 340 nm, using the solution obtained from the reagent blank as the reference. Calculate the change, DA, in absorbance per minute for the solution obtained from the Assay preparation, starting at the point when the absorbance and time relationship becomes linear. One enzyme activity unit is defined as the amount of enzyme that oxidizes 1 µmol of acetaldehyde per minute when the test is conducted under the conditions described herein. Calculate the enzyme activity units in each mg of aldehyde dehydrogenase taken by the formula: in which DA is as defined above and W is the weight, in g, of aldehyde dehydrogenase taken.

Arsenic— Place 750 mg in a generator bottle (see Arsenic in Reagents under General Tests for Reagents), omitting the pledget of cotton. Add 10 mL of water and 10 mL of sodium hydroxide solution (3 in 10), and allow the reaction to proceed for 30 minutes: not more than a barely perceptible stain is produced on the mercuric bromide test paper.

pH of Slurry— The pH of a well-mixed slurry of 5 g in 150 mL of ammonia-free and carbon dioxide-free water, after 10 minutes' standing, is between 3.5 and 4.5.

Loss on ignition— Weigh accurately about 1 g, and ignite, preferably in a muffle furnace at 800 to 825, to constant weight: it loses not more than 5.0% of its weight.

Silica— Fuse 500 mg with 10 g of potassium bisulfate for 1 hour in a platinum crucible, cool, and dissolve in hot water: not more than a small amount of insoluble matter remains.

Suitability for chromatographic adsorption— Dissolve 50 mg of o-nitroaniline in benzene to make 50.0 mL. Dilute 10 mL of the resulting solution with benzene to 100.0 mL, and mix (Solution A).

Nitrogen content (Reagent test)— Determine by the Kjeldahl method, using a test specimen previously dried at 105 for 2 hours: between 18.4% and 18.8% of N is found, corresponding to not less than 98.5% of C2H5NO2.

Insoluble matter (Reagent test): not more than 1 mg, from 10 g (0.01%).

Residue on ignition (Reagent test): not more than 0.05%.

Chloride (Reagent test)— One g shows not more than 0.1 mg of Cl (0.01%).

Sulfate (Reagent test, Method I)— Two g shows not more than 0.1 mg of SO4 (0.005%).

Heavy metals (Reagent test): 0.001%, 5 mL of 1 N hydrochloric acid VS being used to acidify the solution of the test specimen.

Iron 241— One g, dissolved in 47 mL of water containing 3 mL of hydrochloric acid, shows not more than 0.01 mg of Fe (0.001%).

Melting range 741: between 108 and 110.

Melting range 741: between 49 and 52.

Residue on ignition (Reagent test): not more than 2 mg from 2 g (0.1%).

Absorbance— A 1 in 200,000 solution in methanol exhibits absorbance maxima at about 223 nm, 265 nm, and 312 nm. Its absorptivity (see Spectrophotometry and Light-Scattering 851) at 265 nm is about 64.0.

Melting range 741: between 208 and 212.

Ordinary impurities 466—

Test solution: 1 N ammonium hydroxide.

Standard solution: 1 N ammonium hydroxide.

Eluant: 0.5 N sodium chloride.

Visualization: 1.

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 × 30-m capillary column coated with G2. The injection port temperature is maintained at 280; the column temperature is maintained at 180 and programmed to rise 10 per minute to 280 and held there for 10 minutes. The detector temperature is maintained at 300. The area of the main peak is not less than 97% of the total peak area.

Refractive index 831: between 1.4978 and 1.5010 at 20.

Assay— Dissolve about 34 mg, accurately weighed, in 50 mL of glacial acetic acid. Titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Perform a blank determination, and make any necessary corrections. Each mL of 0.1 N perchloric acid is equivalent to 13.61 mg of CH6N4·H2CO3. Not less than 98.5% is found.

Melting point 741: about 170, with decomposition.

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 × 30-m capillary column coated with G2. The injection port temperature is maintained at 180; the column temperature is maintained at 80 and programmed to rise 10 per minute to 230 and then maintained at 230 for 5 minutes. The detector temperature is maintained at 300. The area of the main peak is not less than 95% of the total peak area.

Refractive index 831: between 1.4840 and 1.4860 at 20.

Add the following:

Sensitiveness— Dissolve 100 mg in 50 mL of freshly prepared sodium bisulfite solution (1 in 5), warming if necessary to effect solution, and filter. Add 1 mL of the filtrate to a solution prepared by adding 2 mL of dilute sulfuric acid (1 in 6) and 1 mL of Phosphate Reagent A (see Reagent test) to 20 mL of a 1 in 100 dilution of Standard Phosphate Solution (see Reagent test): a distinct blue color develops within 5 minutes.

Solubility in sodium carbonate solution— Dissolve 100 mg in 3 mL of sodium carbonate TS, and add 17 mL of water: not more than a trace remains undissolved.

Residue on ignition (Reagent test)— To 1 g add 0.5 mL of sulfuric acid, and ignite at 800 ± 25 to constant weight: the residue weighs not more than 5 mg (0.5%).

Sulfate (Reagent test, Method I)— Heat 500 mg with a mixture of 25 mL of water and 2 drops of hydrochloric acid on a steam bath for 10 minutes. Cool, dilute with water to 200 mL, and filter: 20 mL of the filtrate shows not more than 0.25 mg of SO4 (0.5%).

Assay— Dissolve about 1.5 g, accurately weighed, in about 400 mL of water in a 500-mL volumetric flask, dilute with water to volume, and mix. Transfer 25.0 mL of this solution to an iodine flask, add 50.0 mL of 0.1 N bromine VS, dilute with 50 mL of water, add 5 mL of hydrochloric acid, and immediately insert the stopper in the flask. Shake for 1 minute, allow to stand for 2 minutes, and add 5 mL of potassium iodide TS through the slightly loosened 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, adding the rinsing to the flask. Titrate the liberated iodine with 0.1 N sodium thiosulfate VS, adding 3 mL of starch TS as the endpoint is approached. From the volume of 0.1 N sodium thiosulfate used, calculate the volume, in mL, of 0.1 N bromine consumed by the test specimen. Each mL of 0.1 N bromine is equivalent to 1.819 mg of C6H7NO: not less than 99.5% is found.

Melting range 741: between 121 and 123.

Loss on drying 731— Dry it over calcium chloride for 4 hours: the loss in weight is negligible.

Residue on ignition (Reagent test): negligible, from 2 g.

Melting range 741 : between 187 and 189.

Boiling range (Reagent test): between 184 and 188.

Refractive index 831 : between 1.461 and 1.463 at 20.

Measuring range: 5 to 70 ppm.

Assay— Dissolve about 300 mg, accurately weighed, in 50 mL of a mixture of water and alcohol (25:25). Titrate with 0.1 N sodium hydroxide VS, determining the endpoint potentiometrically. Perform a blank determination and make any necessary correction. Each mL of 0.1 N sodium hydroxide is equivalent to 11.51 mg of NH4HSO4. Not less than 98% is found.

Sensitiveness— Dissolve 50 mg in 10 mL of water. Add 0.2 mL of the solution to 1 mL of a solution of 10 mg of choline chloride in 20 mL of water, and shake gently: a distinct precipitate forms within 5 to 10 seconds.

Assay— Weigh accurately about 500 mg, transfer to a suitable container, add 30 mL of water and 2 mL of dilute sulfuric acid (1 in 4), swirl to dissolve, and pass sulfur dioxide gas through the solution until reduction is complete and the solution is bright blue in color. Boil gently while passing a stream of carbon dioxide through the solution to remove any excess sulfur dioxide, then cool, and titrate with 0.1 N potassium permanganate VS. Each mL of 0.1 N potassium permanganate consumed is equivalent to 11.7 mg of NH4VO3. Not less than 98.0% is found.

Solubility in ammonium hydroxide— Dissolve 1 g in a mixture of 3 mL of ammonium hydroxide and 50 mL of warm water: the solution is clear and colorless.

Carbonate— To 500 mg add 1 mL of water and 2 mL of diluted hydrochloric acid: no effervescence is produced.

Chloride— Dissolve 250 mg in 40 mL of hot water, add 2 mL of nitric acid, and allow to stand for 1 hour. Filter, and to the filtrate add 0.5 mL of silver nitrate TS: any turbidity produced does not exceed that of a blank containing 0.5 mg of added Cl (0.2%).

Sulfate— Dissolve 500 mg in 50 mL of hot water, and add 2 mL of diluted hydrochloric acid and 1.5 g of hydroxylamine hydrochloride. Heat at 60 for 3 minutes, filter, cool, and add to the filtrate 2 mL of barium chloride TS: no turbidity or precipitate is produced within 30 minutes.

Specific gravity 841: about 0.87.

Boiling range (Reagent test, Method I): not less than 90%, between 137 and 142.

Solubility in diluted alcohol— A 1.0-mL portion dissolves in 20 mL of diluted alcohol to form a clear solution.

Acidity— Add 5.0 mL to 40 mL of neutralized alcohol, and, if the pink color is discharged, titrate with 0.10 N sodium hydroxide: not more than 0.20 mL is required to restore the pink color (about 0.02% as CH3COOH).

Water— A 5-mL portion gives a clear solution with 5 mL of carbon disulfide.

Specific gravity 841: about 0.81.

Boiling range (Reagent test): not less than 95%, between 100 and 103.

Residue on evaporation— Evaporate 50 mL (40 g) on a steam bath, and dry at 105 for 1 hour: the residue weighs not more than 1.6 mg (0.004%).

Acids and esters— Dilute 20 mL with 20 mL of alcohol, add 5.0 mL of 0.1 N sodium hydroxide VS, and reflux gently for 10 minutes. Cool, add 2 drops of phenolphthalein TS, and titrate the excess sodium hydroxide with 0.1 N hydrochloric acid VS: not more than 0.75 mL of the 0.10 N sodium hydroxide is consumed, correction being made for the amount consumed in a blank (0.06% as amyl acetate).

Aldehydes— Shake 5 mL with 5 mL of potassium hydroxide solution (30 in 100) in a glass-stoppered cylinder for 5 minutes, and allow to separate: no color develops in either layer.

Change to read:

Moisture content of fully regenerated and expanded resin— Transfer 10 to 12 mL of the resin (as received) to a flask, and convert it completely to the chloride form by stirring with 150 mL of hydrochloric acid (5 in 100) for not less than 30 minutes. Decant the acid, and wash the resin in the same manner with distilled water until the wash water is neutral to litmus.

Total new volume capacity— Transfer 2.5 to 3 mL of the conditioned, undried (See Moisture content, above) resin to a 5-mL graduated cylinder, and fill it with water. Remove any air bubbles from the resin bed with a stainless steel wire, and settle the resin to its minimum volume by tapping the graduated cylinder. Record the volume of the resin.

Wet screen analysis— The purpose of this test is to identify properly the mesh size of the resin. To obtain an accurate screen analysis requires special apparatus and technique.

Boiling temperature: 248.

Density: between 1.119 and 1.123.

Refractive index 831: between 1.5725 and 1.5730 at 20.

Assay— Inject an appropriate specimen (about 0.5 µL) into a suitable gas chromatograph (see Chromatography 621) equipped with a flame-ionization detector, nitrogen being used as the carrier gas. The following conditions have been found suitable: a 30-m capillary column is coated with phase G3; the injection port and detector temperatures are maintained at 140 and 300, respectively; the column temperature is maintained at 70 and programmed to rise 10 per minute to 170. The area of the anisole peak is not less than 99% of the total peak area.

Refractive index 831: 1.5160 at 20.

Melting range 741 : between 215 and 218.

Caution—Antimony pentachloride causes severe burns, and the vapor is hazardous.

Assay (SbCl5)— Accurately weigh a glass-stoppered, 125-mL flask, quickly introduce about 0.3 mL of the test specimen, and reweigh. Dissolve with 20 mL of diluted hydrochloric acid (1 in 5), and add 10 mL of potassium iodide solution (1 in 10) and 1 mL of carbon disulfide. Titrate the liberated iodine with 0.1 N sodium thiosulfate VS. The brown color will gradually disappear from the solution, and the last traces of free iodine will be collected in the carbon disulfide, giving a pink color. When this pink color disappears the endpoint has been reached. Each mL of 0.1 N sodium thiosulfate is equivalent to 14.95 mg of SbCl5: not less than 99.0% of SbCl5 is found.

Sulfate (Reagent test, Method II)— Dissolve 4.3 mL (10 g) in the minimum volume of hydrochloric acid, dilute with water to 150 mL, neutralize with ammonium hydroxide, and filter. To the filtrate add 2 mL of hydrochloric acid: the solution, 10 mL of barium chloride TS being used, yields not more than 1.3 mg of residue, correction being made for a complete blank test (0.005%).

Arsenic— Add 10 mL of a recently prepared solution of 20 g of stannous chloride in 30 mL of hydrochloric acid to 100 mg of specimen dissolved in 5 mL of hydrochloric acid. Mix, transfer to a color-comparison tube, and allow to stand for 30 minutes. Any color in the solution of the specimen should not be darker than that in a control containing 0.02 mg of arsenic (As), which has been treated in the same manner as the test specimen, when viewed downward over a white surface (0.02% of As).

Substances not precipitated by hydrogen sulfide (as SO4)— Dissolve 0.90 mL (2 g) in 5 mL of hydrochloric acid, and dilute with 95 mL of water. Precipitate the antimony completely with hydrogen sulfide, allow the precipitate to settle, and filter, being careful not to transfer much of the precipitate to the filter paper. (Retain the precipitate.) To 50 mL of the filtrate, add 0.5 mL of sulfuric acid, evaporate in a tared porcelain crucible to dryness, and ignite at 800 ± 25 for 15 minutes. (Retain the residue.) The weight of the ignited residue should not be more than 0.0010 g greater than the weight obtained in a complete blank test (0.10%).

Iron 241— To the residue from the test for Substances not precipitated by hydrogen sulfide add 2 mL of hydrochloric acid and 5 drops of nitric acid, and evaporate on a steam bath to dryness. Take up the residue in 2 mL of hydrochloric acid, and dilute with water to 47 mL: the solution shows not more than 0.01 mg of Fe (0.001%).

Other heavy metals (as Pb)— Dissolve the precipitate on the filter paper from the test for Substances not precipitated by hydrogen sulfide, with 75 mL of a solution containing 6 g of sodium sulfide and 4 g of sodium hydroxide dissolved in and diluted with water to 100 mL. Collect the filtrate in the original flask containing the remainder of the sulfide precipitate. Warm the solution to dissolve the soluble sulfides, and allow the insoluble sulfides to settle. Filter, wash thoroughly with hydrogen sulfide TS, and dissolve any precipitate remaining on the filter paper with 10 mL of hot diluted hydrochloric acid. Dilute the filtrate with water to 50 mL. Neutralize a 25-mL portion of this solution with 1 N sodium hydroxide, and add 1 mL of 1 N acetic acid and 10 mL of hydrogen sulfide TS. Any brown color should not exceed that produced by 0.05 mg of lead ion in an equal volume of solution containing 1 mL of 1 N acetic acid and 10 mL of hydrogen sulfide TS (0.005%).

Assay— Dissolve about 200 mg, previously dried at 105 for 2 hours and accurately weighed, in 20 mL of dimethylformamide in a 100-mL conical flask. Add 4 drops of thymol blue solution (1 in 200 in methanol), and titrate with 0.1 N lithium methoxide VS using a 10-mL buret, a magnetic stirrer, and a cover for the flask to protect against atmospheric carbon dioxide. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N lithium methoxide is equivalent to 21.02 mg of C10H14N2O3. Between 98.5% and 101.0% of C10H14N2O3 is found.

Melting range 741: between 140 and 143.

Melting temperature 741: greater than 320.

[note—Arsenic Trioxide of a quality suitable as a primary standard is available from the National Institute of Standards and Technology, Office of Standard Reference Materials, www.nist.gov, as standard sample No. 83.]

Specific rotation 781 : between +31 and +33, determined in a solution in diluted hydrochloric acid containing the equivalent of 5 g (on the anhydrous basis, as determined by drying at 105 for 5 hours) in each 100 mL.

Residue on ignition (Reagent test): not more than 0.1%.

Chloride (Reagent test)— One g shows not more than 0.03 mg of Cl (0.003%).

Sulfate (Reagent test, Method I )— One g shows not more than 0.05 mg of SO4 (0.005%).

Heavy metals (Reagent test): 0.002%.

Nitrogen content, Method II461: between 18.4% and 18.8% of N is found.