Acacia (5 g/l) TS.

A solution in water containing about 5 g of acacia R per litre.

Acacia R.

The dried gummy exudate from the stems and branches of Acacia senegal (L.) Willd. and of other species of Acacia of African origin.

Description. Rounded or ovoid tears of varying diameters from about 1 cm to 3 cm; yellowish white or pale amber; odourless.

Solubility. Very slowly soluble in twice its weight of water, leaving only a very small residue of vegetable particles; practically insoluble in ethanol (~750 g/l) TS and ether R.

Ash. Not more than 50 mg/g.

Acid-insoluble ash. Not more than 5.0 mg/g.

Insoluble matter. Mix 5 g of powdered or finely ground material with 100 ml of water and 10 ml of hydrochloric acid (~70 g/l) TS and boil gently for 15 minutes, stirring frequently. Filter while hot through a sintered glass crucible, wash the residue with hot water, and dry to constant weight at 105 °C; not more than 5 mg/g.

Tannin. Dissolve 1 g in 10 ml of water and add 0.1 ml of ferric chloride (25 g/l) TS; no bluish black colour or blackish precipitate is produced.

Acetaldehyde R.

Ethanal; C₂H₄O.

Description. A clear, colourless, flammable liquid.

Miscibility. Miscible with water and ethanol (~750 g/l) TS.

Refractive index. = 1.332

Relative density. = 0.788

Boiling point. About 21°C.

p-Acetamidobenzalazine RS.

International Chemical Reference Substance.

Acetate buffer, pH 3.0, TS.

A buffer mixture of pH 3.0.

Procedure. Dissolve 12 g of sodium acetate R in water, add 6 ml of glacial acetic acid R and dilute with sufficient water to produce 100 ml.

Acetate buffer, pH 4.5, TS.

Procedure. Dissolve 10.9 g of sodium acetate R in 100 ml of water, add 8 ml of glacial acetic acid R, mix, and dilute to 1000 ml with water.

Acetate buffer, pH 4.6, TS

Procedure. Dissolve 5.4 g of sodium acetate R in 50 ml of water, adjust to pH 4.6 with glacial acetic acid R, and dilute to 100 ml with water.

Acetate buffer, pH 4.7, TS.

Procedure. Dissolve 8.4 g of sodium acetate R in 100 ml of water, add 3.35 ml of glacial acetic acid R, mix, and dilute to 1000 ml with water.

Acetate buffer, pH 5.0, TS.

Procedure. Dissolve 13.6 g of sodium acetate R in 100 ml of water, add 6 ml of glacial acetic acid R, mix, and dilute to 1000 ml with water.

Acetate buffer, pH 5.5, TS.

Procedure. Dissolve 54.4 g of sodium acetate R in 50 ml of water, heating to 35 °C, if necessary. After cooling, slowly add 10 ml of glacial acetic acid R. Shake and dilute to 1000 ml with water.

Acetate buffer, pH 6.0, TS

Procedure. Dissolve 100 g of ammonium acetate R in 300 ml of water. Add 4.1 ml of glacial acetic acid R, adjust the pH to 6.0 using either ammonia (~100 g/l) TS or acetic acid (~300 g/l) TS, and dilute to 500 ml with water.

Acetate standard buffer TS.

Procedure. To 10 ml of acetic acid (~60 g/l) TS add 10 ml of sodium hydroxide (1 mol/l) VS and dilute with sufficient carbon-dioxide-free water R to produce 1000 ml.

Acetazolamide RS.

International Chemical Reference Substance.

Acetic acid (~90 g/l) TS.

Acetic acid (~300 g/l) TS, diluted with water to contain about 90 g of C₂H₄O₂ per litre (approximately 1.5 mol/l).

Acetic acid (~120 g/l) TS.

Acetic acid (~300 g/l) TS, diluted with water to contain 120 g of C₂H₄O₂ per litre (approximately 2 mol/l); d~1.016.

Acetic acid (~300 g/l) TS.

A solution of glacial acetic acid R containing about 300 g/l of C₂H₄O₂ (approximately 5 mol/l); d ~ 1.037.

Acetic acid (~60 g/l) PbTS.

Acetic acid (~60 g/l) TS that complies with the following test: Evaporate 20 ml of acetic acid (~60 g/l) TS almost to dryness on a water-bath, add 25 ml of water and carry out the test for heavy metals. The heavy metals limit is 3 μg/ml.

Acetic acid (~60 g/l) TS.

Acetic acid (~300 g/l) TS, diluted to contain about 60 g/l of C₂H₄O₂ (approximately 1 mol/l); d ~ 1.008.

Acetic acid (0.07 mol/l) VS.

A solution prepared by diluting 4.2 ml of glacial acetic acid R to 1000 ml with water.

Acetic acid (5.0 g/l) TS.

Acetic acid (~300 g/l) TS, diluted with water to contain about 5.0 g of C₂H₄O₂ per litre; d~1.0007.

Acetic acid, anhydrous.

Glacial acetic acid R for use in non-aqueous titrations containing not less than 99.6% w/w of C₂H₄O₂ and that complies with the following test:

Water. Not more than 4 mg/g, determined as described under 2.8 Determination of water by the Karl Fischer method, Method A. If the water content is greater than 4 mg/g it may be adjusted by adding the calculated amount of acetic anhydride R.

Acetic acid, glacial, R.

C₂H₄O₂ (SRIP, 1963, p. 25); d ~ 1.048.

Acetic acid, glacial, R1.

Glacial acetic acid R, that complies with the following tests:

Substances reducing dichromate. To 10 ml add 1.0 ml of potassium dichromate (0.0167 mol/l) VS and cautiously add 10 ml of sulfuric acid (~1760 g/l) TS. Cool the solution to room temperature and allow to stand for 30 minutes. While swirling the solution, dilute slowly and cautiously with 50 ml of water, cool, and add 1.5 ml of freshly prepared potassium iodide (80 g/l) TS. Titrate the liberated iodine with sodium thiosulfate (0.1 mol/l) VS, adding 3 ml of starch TS as the end-point is approached. Perform a blank titration and make any necessary corrections. Not less than 0.60 ml of sodium thiosulfate (0.1 mol/l) VS is consumed.

Substances reducing permanganate. Add 40 ml to 10 ml of water. Cool to 15°C, add 0.30 ml of potassium permanganate (0.02 mol/l) VS, and allow to stand at 15°C for 10 minutes; the pink colour is not entirely discharged.

Acetic anhydride R.

C₄H₆O₃ (SRIP, 1963, p. 26).

Acetic anhydride/dioxan TS.

Procedure. To 50 ml of dioxan R add 1 ml of acetic anhydride R (approximately 0.2 mol/l).

Acetone R.

C₃H₆O (SRIP, 1963, p. 27).

Acetonitrile (400 g/l) TS.

Procedure. Mix 1 volume of acetonitrile R with 1 volume of water. The resulting solution contains about 400 g/l of C₂H₃N.

Acetonitrile R.

Methyl cyanide, C₂H₃N.

Description. A clear, colourless liquid.

Miscibility. Freely miscible with water.

Acetyl chloride R.

C₂H₃ClO. Contains not less than 98.0% of C₂H₃ClO in both assay A and assay B (see below).

Description. A clear, colourless or very slightly yellow liquid.

Phosphorus compounds. Carefully treat 1 ml with 1 ml of water, add 1 ml of nitric acid (~1000 g/l) TS, boil, cool, dilute with 20 ml of water, add 10 ml of ammonium molybdate/nitric acid TS and allow to stand at about 40°C for 2 hours; no yellow precipitate is produced.

Assay. (A) Dissolve about 1 g, accurately weighed, in 50 ml of carbonate-free sodium hydroxide (1 mol/l) VS, and titrate with sulfuric acid (0.5 mol/l) VS, using phenolphthalein/ethanol TS as indicator. Each ml of carbonate-free sodium hydroxide (1 mol/l) VS is equivalent to 7.850 mg of C₂H₃ClO. (B) Dilute the neutralized liquid from A to 250 ml with water, mix, and titrate 50 ml with silver nitrate (0.1 mol/l) VS, using potassium chromate (100 g/l) TS as indicator. Each ml of silver nitrate (0.1 mol/l) VS is equivalent to 7.850 g of C₂H₃ClO.

Agar R.

(SRIP, 1963, p. 27).

Albendazole RS.

International Chemical Reference Substance.

Alcuronium chloride RS.

International Chemical Reference Substance.

Allopurinol RS.

International Chemical Reference Substance.

Alum R.

Aluminium potassium sulfate dodecahydrate; KAl(SO₄)₂,12H₂O (SRIP, 1963, p. 29).

Aluminium chloride R.

AlCl₃,6H₂O (SRIP, 1963, p. 30).

Aluminium chloride TS.

Procedure. Dissolve 65.0 g of aluminium chloride R in sufficient water to produce 100 ml, add 0.5 g of charcoal R, stir for 10 minutes and filter. While stirring, add to the filtrate sufficient sodium hydroxide (0.5 mol/l) VS to adjust the pH to 1.5.

Aluminium hydroxide R.

Hydrated Al(OH)₃.

Description. A white, odourless powder.

Solubility. Practically insoluble in water and in ethanol (~750 g/l) TS.

Aluminium oxide R.

Al₂O₃.

A suitable grade for use in thin-layer chromatography.

Aluminium R.

Al (SRIP, 1963, p. 29); wire, granules, or sheets.

Aluminium standard (2 ppm Al) TS.

Procedure. Immediately before use, dilute with water R to 100 times its volume a solution containing aluminium potassium sulphate R equivalent to 0.352 g of AlK(SO₄)₂, 12H₂O and 10 ml of diluted sulphuric acid R in 100 ml.

Aluminium standard (10 μg Al/ml) TS

Procedure. Dissolve 17.6 mg of alum R in 5 ml of sulfuric acid (0.05 mol/l) VS and dilute to 100 ml with water.

Note. For the preparation of this test solution commercially available aluminium nitrate standard solution 1000 μg Al³⁺/ml or aluminium nitrate nonahydrate can also be used.

Amidotrizoic acid RS.

International Chemical Reference Substance.

Amiloride hydrochloride RS.

International Chemical Reference Substance.

3-Amino-2,4,6-triiodobenzoic acid RS.

International Chemical Reference Substance.

2-Amino-5-nitrothiazole R.

C₃H₃N₃O₂S.

Description. Greenish yellow to orange-yellow, fluffy powder.

Solubility. Very slightly soluble in water; soluble in dilute mineral acids; slightly soluble in ethanol (~750 g/l) TS and ether R.

Melting temperature. About 198 °C with decomposition.

4-Amino-6-chloro-1,3-benzenedisulfonamide R.

C₆H₈ClN₃O₄S₂.

Description. A white, odourless powder.

Solubility. Soluble in ammonia (~100 g/l) TS; practically insoluble in water.

Identification. The absorption spectrum of a 5 μg/ml solution in methanol R exhibits maxima at about 223 nm, 265 nm, and 312 nm. The absorptivity at 265 nm is about 64.0 ( = 640).

Sulfated ash. Ignite 2 g; not more than 1.0 mg/g.

4-Aminoantipyrine R.

C₁₁H₁₃N₃O. 4-Amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one; ampyrone; aminopyrazolone.

Description. Pale yellow crystals or powder.

Solubility. Sparingly soluble in water; freely soluble in ethanol (~750 g/l) TS; very slightly soluble in ether R.

Melting temperature. About 108 °C.

4-Aminoantipyrine TS1.

Procedure. Dissolve 0.125 g of 4-aminoantipyrine R in 25 ml of methanol R containing 0.25 ml of hydrochloric acid (~420 g/l) TS.

4-Aminoantipyrine TS2.

Procedure. Dissolve about 0.1 g of 4-aminoantipyrine R in 30 ml of water and add a mixture of 10 ml of sodium carbonate (200 g/l) TS and 2 ml of sodium hydroxide (1 mol/l) VS; dilute with sufficient water to produce 100 ml.

Note: 4-Aminoantipyrine TS2 must be freshly prepared.

4-Aminobenzoic acid R.

C₇H₇NO₂. Contains not less than 98.5% of C₇H₇NO₂.

Description. White or slightly yellow crystals or a crystalline powder; odourless.

Solubility. Soluble in 170 parts of water, in 9 parts of boiling water, in 8 parts of ethanol (~750 g/l) TS, and in 50 parts of ether R.

Melting range. 186-189°C.

Sulfated ash. Not more than 1.0 mg/g.

Loss on drying. Dry at 105°C for 2 hours; it loses not more than 2.0 mg/g.

Assay. Transfer to a beaker about 0.3 g, accurately weighed and previously dried at 105°C for 2 hours, add 5 ml of hydrochloric acid (~420 g/l) TS, 50 ml of water and stir until dissolved. Cool to about 15°C, add about 25 g of crushed ice and slowly titrate with sodium nitrite (0.1 mol/l) VS until a glass rod dipped into the titrated solution produces an immediate blue ring when touched to starch/iodide paper R. When the titration is complete, the end-point is reproducible after the mixture has been allowed to stand for 1 minute. Each ml of sodium nitrite (0.1 mol/l) VS is equivalent to 13.71 mg of C₇H₇NO₂.

Storage. Store in a tightly closed container, protected from light.

2-Aminobutanol R.

C₄H₁₁NO.

Description. A colourless or light yellow, clear liquid.

Miscibility. Miscible with water and methanol R.

Mass density. ρ₂₀ = 0.944-0.950 kg/l.

Refractive index. = 1.450 - 1.455.

Identification. Dissolve 0.05 g in 4 ml of ethanol (~750 g/l) TS, add 0.5 ml of a 2.5 mg/ml solution of triketohydrindene hydrate R and warm on a water-bath; a violet colour is produced.

7-[(2-Aminoethyl)amino]-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid RS

(ciprofloxacin ethylenediamine compound).

International Chemical Reference Substance.

4-Aminophenol R.

C₆H₇NO.

Description. A white or almost white, crystalline powder.

Melting temperature. About 184 °C with decomposition.

Aminopolyether R.

4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo[8,8,8]hexacosane ; C₁₈H₃₆N₂O₆.

A commercially available reagent of suitable grade.

Melting point. 70 °C to 73 °C.

3-Aminopyrazole-4-carboxamide hemisulfate RS.

International Chemical Reference Substance.

Amitriptyline hydrochloride RS.

International Chemical Reference Substance.

Ammonia (~100 g/l) FeTS.

Ammonia (~100 g/l) TS that complies with the following test: Evaporate 5 ml of ammonia (~100 g/l) TS nearly to dryness on a water-bath, add 40 ml of water, 2 ml of citric acid (180 g/l) FeTS, and 2 drops of mercaptoacetic acid R; mix, make alkaline with ammonia (~100 g/l) FeTS, and dilute to 50 ml with water; no pink colour is produced.

Ammonia (~100 g/l) PbTS.

Ammonia (~100 g/l) TS that complies with the following test: Evaporate 5 ml of ammonia (~100 g/l) TS to dryness on a water-bath, add to the residue 1 ml of hydrochloric acid (~70 g/l) TS, and evaporate to dryness. Dissolve the residue in 2 ml of acetic acid (~60 g/l) PbTS, dilute with water to 25 ml and carry out the test for heavy metals. Prepare the blank in a similar way. The heavy metals limit is 2 μg/ml.

Ammonia (~100 g/l) TS.

Ammonia (~260 g/l) TS, diluted to contain about 100 g/l of NH₃ (approximately 6 mol/l); d ~ 0.956.

Ammonia (~17 g/l) TS.

Ammonia (~100 g/l) TS, diluted to contain about 17 g of NH₃ per litre (approximately 1 mol/l); d ~ 0.992.

Ammonia (~260 g/l) TS

[ammonia, strong, R]. (SRIP, 1963, p. 31); d ~ 0.894.

Ammonia (~35 g/l) TS.

Ammonia (~100 g/l) TS, diluted to contain about 35 g of NH₃ per litre (approximately 2 mol/l); d ~ 0.985.

Ammonia (~50 g/l) TS.

Ammonia (~260 g/l) TS, diluted with water to contain about 50 g of NH₃ per litre (approximately 3 mol/l); d~0.977.

Ammonia buffer TS.

Procedure. Dissolve 67.5 g of ammonium chloride R in 570 ml of ammonia (~260 g/l) TS and dilute with water to 1000 ml.

Ammonia buffer TS2.

Procedure. Dissolve 67.5 g of ammonium chloride R in 650 ml of ammonia (~260 g/l) TS and dilute with water to produce 1000 ml.

Ammonium acetate (100 g/l) TS.

A solution of ammonium acetate R containing 100 g of C₂H₇NO₂ per litre.

Ammonium acetate (2 g/l) TS.

A solution of ammonium acetate R containing about 2 g of C₂H₇NO₂ per litre.

Note: Ammonium acetate (2 g/l) TS must be freshly prepared.

Ammonium acetate (40 g/l) TS.

A solution of ammonium acetate R containing about 38.5 g of C₂H₇NO₂ per litre (approximately 0.5 mol/l).

Note: Ammonium acetate (40 g/l) TS must be freshly prepared.

Ammonium acetate (50g/l) TS.

A solution of ammonium acetate R containing about 50 g of C₂H₇NO₂ per litre.

Ammonium acetate (80 g/l) TS.

A solution of ammonium acetate R containing about 77 g/l of C₂H₇NO₂ (approximately 1 mol/l).

Ammonium acetate TS

Procedure. Dissolve 150 g of ammonium acetate R in water, add 3 ml of glacial acetic acid R, and dilute with sufficient water to produce 1000 ml.

Note: Ammonium acetate TS must be used within 1 week of preparation.

Ammonium acetate buffer, pH 4.62, TS.

Procedure. Adjust the pH of ammonium acetate (100 g/l) TS to 4.62 using acetic acid (~60 g/l) TS.

Ammonium acetate R.

C₂H₇NO₂ (SRIP, 1963, p. 32).

Ammonium carbonate R.

(NH₄)₂CO₃ (SRIP, 1963, p. 33).

Ammonium chloride (10 μg/ml NH₄) TS.

Procedure. Dissolve 0.296 g, accurately weighed, of ammonium chloride R in sufficient water to produce 1000 ml. Dilute 10 ml of this solution to 100 ml.

Shelf-life. Use the solution within 2 weeks of its preparation.

Ammonium chloride (100 g/l) TS.

A solution of ammonium chloride R containing about 100 g of NH₄Cl per litre.

Ammonium chloride (20g/l) TS.

A solution of ammonium chloride R containing about 20g of NH₄Cl per litre.

Ammonium chloride buffer, pH 10.0, TS.

A buffer mixture of pH 10.0.

Procedure. Dissolve 7.0 g of ammonium chloride R in 57 ml of ammonia (~260 g/l) TS and dilute with sufficient water to produce 100 ml.

Ammonium chloride buffer, pH 10.5, TS.

A buffer mixture of pH 10.5.

Procedure. Dissolve 6.95 g of ammonium chloride R in 75 ml of ammonia (~260 g/l) TS and dilute to 100 ml with water.

Ammonium chloride R.

NH₄Cl (SRIP, 1963, p. 33).

Ammonium chloride TS (Nessler's reagent)

Procedure. Dissolve 3.15 g of ammonium chloride R in a sufficient quantity of ammonia-free water R to produce 1000 ml.

Ammonium chloride, dilute, TS

Procedure. To 10 ml of ammonium chloride TS add a sufficient quantity of ammonia-free water R to produce 1000 ml.

Ammonium dihydrogen phosphate

(NH₄)H₂PO₄

Ammonium mercurithiocyanate TS.

Procedure. Dissolve 30 g of ammonium thiocyanate R and 27 g of mercuric chloride R in sufficient water to produce 1000 ml.

Ammonium molybdate (45 g/l) TS.

A solution of ammonium molybdate R containing about 47 g of (NH₄)₆Mo₇O₂₄ per litre.

Ammonium molybdate (95 g/l) TS.

A solution of ammonium molybdate R containing about 95 g/l of (NH₄)₆Mo₇O₂₄.

Ammonium molybdate R.

(NH₄)₆Mo₇O₂₄,4H₂O (SRIP, 1963, p. 34).

Ammonium molybdate/nitric acid TS.

Procedure. Dissolve 50 g of ammonium sulfate R in 500 ml of nitric acid (~1000 g/l) TS using a 2000-ml conical flask or beaker. Dissolve separately in a beaker 150 g of ammonium molybdate R in 400 ml of boiling water. After cooling, pour this solution slowly, while stirring, into the acid solution and dilute with water to 1000 ml. Allow to stand for 2-3 days, and filter.

Storage. Store in well-closed, brown glass bottles, and keep in a cool place.

Ammonium molybdate/sulfuric acid TS.

Procedure. Dissolve 0.5 g of ammonium molybdate R in sufficient sulfuric acid (~1760 g/l) TS to produce 10 ml.

Ammonium molybdate/vanadate TS.

Procedure. Shake 4 g of finely powdered ammonium molybdate R and 0.1 g of finely powdered ammonium vanadate R with 70 ml of water. Add 20 ml of nitric acid (~1000 g/l) TS and dilute to 100 ml with water.

Ammonium nitrate (50 g/l) TS.

A solution of ammonium nitrate R containing about 50 g of NH₄NO₃ per litre.

Ammonium nitrate R.

NH₄NO₃ (SRIP, 1963, p. 35).

Ammonium nitrate TS

Procedure. Dissolve 1.6 g of ammonium nitrate R in 30 ml of water, add 3.0 ml of ammonia (~260g/l) TS, and dilute with sufficient water to produce 100 ml.

Ammonium oxalate (25 g/l) TS.

A solution of ammonium oxalate R containing about 27 g/l of C₂H₈N₂O₄.

Ammonium oxalate (50 g/l) TS.

A solution of ammonium oxalate R containing about 50 g of C₂H₈N₂O₄ per litre.

Ammonium oxalate R.

C₂H₈N₂O₄,H₂O (SRIP, 1963, p. 36).

Ammonium persulfate R.

(NH₄)₂S₂O₈ (SRIP, 1963, p. 37).

Ammonium persulfate/phosphate buffer TS.

Procedure. Dissolve 10 g of ammonium persulfate R in sufficient phosphate buffer, pH 7.4, TS to produce 100 ml.

Ammonium pyrrolidinedithiocarbamate (10 g/l) TS

Procedure. Immediately before use, wash 10 g of ammonium pyrrolidinedithiocarbamate R three times, each with 25 ml of isobutyl methyl ketone R, filter, and dry the substance. Then dissolve 1.0 g in sufficient water to produce 100 ml.

Ammonium pyrrolidinedithiocarbamate R.

Ammonium 1-pyrrolidinecarbodithioate; C₅H₁₂N₂S₂. Reagent grade quality.

Ammonium reineckate (10 g/l) TS.

A solution of ammonium reineckate R containing about 10 g of NH₄[Cr(NH₃)₂(SCN)₄] per litre.

Ammonium reineckate R.

NH₄[Cr(NH₃)₂(SCN)₄],H₂O (SRIP, 1963, p. 39).

Ammonium sulfamate (25 g/l) TS.

A solution of ammonium sulfamate R containing about 25 g of NH₄OSO₂NH₂ per litre.

Ammonium sulfamate (5 g/l) TS.

A solution of ammonium sulfamate R containing about 5 g of NH₄OSO₂NH₂ per litre.

Ammonium sulfamate (50 g/l) TS.

A solution of ammonium sulfamate R containing 50 g of NH₄OSO₂NH₂ per litre.

Ammonium sulfamate R.

NH₄OSO₂NH₂ (SRIP, 1963, p. 39).

Ammonium sulfate R.

(NH₄)₂SO₄ (SRIP, 1963, p. 40).

Ammonium sulfide TS.

Procedure. Prepare a saturated solution of hydrogen sulfide R in ammonia (~100 g/l) TS. To 25 ml of this solution add 50 ml of ammonia (~100 g/l) TS.

Ammonium thiocyanate (0.01 mol/l) VS.

Ammonium thiocyanate R, dissolved in water to contain 0.7612 g of NH₄SCN in 1000 ml.

Method of standardization. Ascertain the exact concentration of the solution following the method described under ammonium thiocyanate (0.1 mol/l) VS.

Ammonium thiocyanate (0.05 mol/l) VS.

Ammonium thiocyanate R, dissolved in water to contain 3.806 g of NH₄SCN in 1000 ml.

Method of standardization. Ascertain the exact concentration of the solution following the method described for ammonium thiocyanate (0.1 mol/l) VS.

Ammonium thiocyanate (0.1 mol/l) VS.

Ammonium thiocyanate R, dissolved in water to contain 7.612 g of NH₄SCN in 1000 ml.

Method of standardization. Ascertain the exact concentration of the 0.1 mol/l solution in the following manner: Place 30.0 ml of silver nitrate (0.1 mol/l) VS in a glass-stoppered flask. Dilute with 50 ml of water, add 2 ml of nitric acid (~1000 g/l) TS and then titrate with the ammonium thiocyanate solution to the first appearance of a red-brown colour, using 2 ml of ferric ammonium sulfate (45 g/l) TS as indicator.

Ammonium thiocyanate (10g/l) TS.

A solution of ammonium thiocyanate R containing 10g of NH₄SCN per litre.

Ammonium thiocyanate (75 g/l) TS.

A solution of ammonium thiocyanate R containing about 75 g/l of NH₄SCN (approximately 1 mol/l).

Ammonium thiocyanate R.

NH₄SCN (SRIP, 1963, p. 40).

Ammonium thiocyanate/cobalt(II) nitrate TS.

Procedure. Dissolve 20 g of ammonium thiocyanate R and 5 g of cobalt(II) nitrate R in 100 ml of water. Add sufficient sodium chloride R to saturate the solution.

Ammonium vanadate R.

NH₄VO₃.

Description. A white to slightly yellowish, crystalline powder.

Solubility. Slightly soluble in water; soluble in ammonia (~100 g/l) TS.

Amodiaquine hydrochloride RS.

International Chemical Reference Substance.

Amoxicillin trihydrate RS.

International Chemical Reference Substance.

Amphotericin B RS.

International Chemical Reference Substance (containing the declared content of tetraenes).

Ampicillin RS.

International Chemical Reference Substance.

Ampicillin sodium RS.

International Chemical Reference Substance.

Ampicillin trihydrate RS.

International Chemical Reference Substance.

Amyl alcohol R.

C₅H₁₂O (SRIP, 1963, p. 42).

Anhydrotetracycline hydrochloride RS.

International Chemical Reference Substance.

Aniline (25 g/l) TS.

A solution of aniline R containing about 25 g of C₆H₇N per litre.

Aniline R.

C₆H₇N (SRIP, 1963, p. 43).

Anisaldehyde R.

4-Methoxybenzaldehyde; C₈H₈O₂.

Description. A colourless to pale yellow, oily liquid.

Solubility. Very slightly soluble in water, miscible with ethanol (~750 g/l) TS and ether R.

Mass density. ρ₂₀ = about 1.125 kg/l.

Boiling point. About 248°C.

Anisaldehyde TS

Procedure. Mix in the following order 0.5 ml of anisaldehyde R, 10 ml of glacial acetic acid R, 85 ml of methanol R, and 5 ml of sulfuric acid (~1760 g/l) TS.

Anisaldehyde/methanol TS

Procedure. Slowly add 10 ml of glacial acetic acid R and 5 ml of sulfuric acid (~1760 g/l) TS to 55 ml of methanol R, and cool to room temperature. Separately add 0.5 ml of anisaldehyde R to 30 ml of methanol R. Mix the two solutions thoroughly.

Storage. Keep anisaldehyde/methanol TS protected from light.

Note: Anisaldehyde/methanol TS should be freshly prepared.

Anisaldehyde/sulfuric acid TS

Procedure. Add 5 ml of anisaldehyde R to 10 ml of sulfuric acid (~1760 g/l) TS.

Anthrone R.

C₁₄H₁₀O.

Description. A pale yellow, crystalline powder.

Solubility. Practically insoluble in water; slightly soluble in ethanol (~750 g/l) TS and in sulfuric acid (~100 g/l) TS.

Solubility in carbon tetrachloride R. Add 0.5 g to 10 ml of carbon tetrachloride R; a clear, non-fluorescent solution is produced.

Melting range. 154-156 °C.

Anthrone TS.

Procedure. Dissolve 35 mg of anthrone R in 100 ml of sulfuric acid (~1760 g/l) TS.

Anthrone TS2

Procedure. Dissolve 200 mg of anthrone R in 100 ml of sulfuric acid (~1760 g/l) TS.

Antimony sodium tartrate (50 g/l) TS.

A solution of antimony sodium tartrate R containing about 50 g/l of C₄H₄NaO₇Sb.

Antimony sodium tartrate R.

C₄H₄NaO₇Sb.

Description. Hygroscopic, transparent or whitish scales or powder.

Solubility. Soluble in 1.5 parts of water; practically insoluble in ethanol (~710 g/l) TS.

Antimony trichloride R.

SbCl₃. Contains not less than 97.0% of SbCl₃.

Description. Colourless crystals.

Solubility. Very soluble in dehydrated ethanol R and in chloroform R (may form a slightly turbid solution).

Chloroform-insoluble substances. Dissolve 5.0 g in 25 ml of chloroform R, filter through a tared filtering crucible, wash the crucible with several portions of chloroform R, and dry at 105°C; it leaves a residue of not more than 1.0 mg.

Assay. Dissolve 0.5 g, accurately weighed, in 30 ml of water containing 4.0 g of potassium sodium tartrate R, add 2 g of sodium hydrogen carbonate R, and titrate with iodine (0.1 mol/l) VS. Each ml of iodine (0.1 mol/l) VS is equivalent to 11.41 mg of SbCl₃.

Note: In moist air fumes may be evolved.

Antimony trichloride TS.

Procedure. Dissolve 22 g of antimony trichloride R in 100 ml of ethanol-free chloroform R, add 2.5 ml of acetyl chloride R, and allow to stand for 30 minutes.

Aprotinin R.

A polypeptide consisting of a chain of 58 amino acids. A commercially available reagent of suitable grade.

Arachis oil R.

Use arachis oil as described in the monograph for "Arachis oil".

Argon R.

Ar. Contains not less than 99.995% of Ar.

Carbon monoxide. When used as described in the test for carbon monoxide in medicinal gases, after passage of 10 litres of argon at a flow rate of 4 litres per hour, not more than 0.05 ml of sodium thiosulfate (0.002 mol/l) VS is required for the titration (0.6 μl/l).

Arsenic trioxide R.

As₂O₃ (SRIP, 1963, p. 44).

Arsenic trioxide R1.

Arsenic trioxide R that has been prepared according to either of the following methods:

1. Recrystallize arsenic trioxide R from a boiling mixture of 20 parts of hydrochloric acid (~420 g/l) TS and 5 parts of water. After cooling, collect the crystals and recrystallize them from boiling water until the mother liquor has a pH greater than 4.0. Dry the crystals to constant weight over silica gel, desiccant, R.

2. Sublime arsenic trioxide R in an appropriate apparatus.

pH value. Heat to boiling for a few minutes 1.0 g in 20 ml of water, filter and cool; the filtrate has a pH greater than 4.0.

Chlorides. Dissolve 10 mg in sufficient water to produce 10 ml. Acidify with 1 drop of nitric acid (~1000 g/l) TS and add 2 drops of silver nitrate (0.1 mol/l) VS; the solution remains clear and colourless for not less than 2 minutes.

Sulfides. To a solution of 5.0 g in a mixture of 10 ml of sodium hydroxide (~80 g/l) TS and 15 ml of water add 2 drops of lead acetate (80 g/l) TS; the solution remains colourless.

Loss on drying. Dry to constant weight over silica gel, desiccant, R; it loses not more than 0.1 mg/g.

Sulfated ash. Not more than 0.1 mg/g.

Arsenic, dilute, AsTS.

One millilitre contains 10 μg of arsenic.

Procedure. Dilute 1 ml of strong arsenic AsTS with sufficient water to produce 100 ml.

Note: Dilute arsenic AsTS must be freshly prepared.

Arsenic, strong, AsTS.

Procedure. Dissolve 0.132 g of arsenic trioxide R in 6 ml of sodium hydroxide (~80 g/l) TS, by gentle heating. Dilute the cooled solution with 20 ml of water, and add 50 ml of hydrochloric acid (~250 g/l) TS and sufficient water to produce 100 ml.

Artemether RS.

International Chemical Reference Substance.

Artemisinin RS.

International Chemical Reference Substance.

Artemotil RS.

International Chemical Reference Substance.

Artenimol RS.

International Chemical Reference Substance.

Artesunate RS.

International Chemical Reference Substance.

Atenolol RS.

International Chemical Reference Substance.

Atenolol for column validation RS.

International Chemical Reference Substance.

Atropine sulfate RS.

International Chemical Reference Substance.

Azathioprine RS.

International Chemical Reference Substance.

Azo violet R.

4-(4-Nitrophenylazo)resorcinol; Magneson I: C₁₂H₉N₃O₄.

Description. A red powder.

Melting temperature. About 193°C with decomposition.

Azo violet TS.

Procedure. Dissolve 0.2 g of azo violet R in a mixture of 1 volume of toluene R and 2 volumes of cyclohexane R.