[대한약전/KP] 정성반응 (Qualitative Tests)(D~Z)

Dichromate

(1) Solutions of dichromates exhibit a yellow-red color.
(2) Solutions of dichromates produce a yellow precipitate with lead acetate TS. When acetic acid is added to one portion of the suspension, the precipitate dose not dissolve. When dilute nitric acid is added to another portion, the precipitate dissolves.
(3) When acidic solutions of dichromates in sulfuric acid are mixed with an equal volume of ethyl acetate and with 1 to 2 drops of hydrogen peroxide TS, shaken immediately and allowed to stand, the ethyl acetate layer exhibits a blue color.

Ferric salt

(1) Slightly acidic solutions of ferric salts yield a blue precipitate with potassium hexacyanoferrate (II) TS. The precipitate does not dissolve in dilute hydrochloric acid subsequently added.
(2) Solutions of ferric salts yield a gelatinous, redbrown precipitate with sodium hydroxide TS. The precipitate changes to black upon addition of sodium sulfide TS. The separated precipitate dissolves in dilute hydrochloric acid, yielding a white turbidity.
(3) Slightly acidic solutions of ferric salts exhibit a purple color with sulfosalicylic acid TS.

Ferricyanide
(1) Solutions of ferricyanides exhibit a yellow color.
(2) Solutions of ferricyanides yield a blue precipitate with iron (II) sulfate TS. The precipitate does not dissolve in dilute hydrochloric acid subsequently added.

Ferrocyanide
(1) Solutions of ferrocyanides yield a blue precipitate with iron (III) chloride TS. The precipitate does not dissolve in dilute hydrochloric acid subsequently added.
(2) Solutions of ferrocyanides yield a red-brown precipitate with copper (II) sulfate TS. The precipitate does not dissolve in dilute hydrochloric acid subsequently added.

Ferrous salt
(1) Slightly acidic solutions of ferrous salts yield a blue precipitate with potassium hexacyanoferrate (III) TS. The precipitate does not dissolve in dilute hydrochloric acid subsequently added.
(2) Solutions of ferrous salts yield a greenish gray, gelatinous precipitate with sodium hydroxide TS. The precipitate changes to black with sodium sulfide TS. The separated precipitate dissolves in dilute hydrochloric acid.
(3) Neutral or slightly acidic solutions of ferrous salts exhibit an intense red color upon drop-wise addition of a solution of o-phenanthroline in ethanol (1 in 50).

 

Fluoride
(1) When solutions of fluorides are heated with chromic acid-sulfuric acid TS, the inside of the test tube is not moistened uniformly.

(2) Neutral or slightly acidic solutions of fluorides exhibit a blue-purple color after standing with 1.5mL of a mixture of alizarin complexone TS, acetic acidpotassium acetate buffer solution, pH 4.3, and cerium (III) nitrate TS(1:1:1).

Glycerophosphate
(1) Solutions of glycerophosphates remain unaffected by addition of calcium chloride TS, but yield a precipitate when boiled.
(2) Solutions of glycerophosphates yield no precipitate with ammonium molybdate TS when cold, but yield a yellow precipitate when boiled for a long time.

(3) When glycerophosphates are mixed with an equal mass of powdered potassium hydrogen sulfate and heated gently over a free flame, the pungent odor of acrolein is evolved.

Iodide
(1) Solutions of iodides yield a yellow precipitate with silver nitrate TS. When dilute nitric acid is added to one portion of the suspension, and ammonia solution(28) to another portion, the precipitates do not dissolve in either of these reagents.
(2) Acidic solutions of iodides exhibit a yellowbrown color with 1 to 2 drops of sodium nitrite TS and then yield a black-purple precipitate. The solutions exhibit a deep-blue color with starch TS subsequently added.

Lactate
Acidic solutions of lactates in sulfuric acid, when heated with potassium permanganate TS, evolve the odor of acetaldehyde.

Lead salt
(1) Solutions of lead salts yield a white precipitate with dilute sulfuric acid. When dilute nitric acid is added to a portion of the separated precipitate, it does not dissolve. When sodium hydroxide TS is added to another portion and warmed, or when ammonium acetate TS is added to another portion, the precipitate dissolves.
(2) Solutions of lead salts yield a white precipitate with sodium hydroxide TS. The precipitate dissolves in an excess of sodium hydroxide TS, and yields a black precipitate upon subsequent addition of sodium sulfide TS.
(3) Acidic solutions of lead salts in dilute acetic acid yield a yellow precipitate with potassium chromate TS. The precipitate does not dissolve in ammonia TS but dissolves in sodium hydroxide TS subsequently added.

 

Lithium salt
(1) When the Flame Coloration Test (1) is applied to lithium salts, a persistent red color develops.

(2) Solutions of lithium salts yield a white precipitate with disodium hydrogen phosphate TS. The precipitate dissolves upon subsequent addition of dilute hydrochloric acid.
(3) Solutions of lithium salts yield no precipitate with dilute sulfuric acid (discrimination from strontium salts).

Magnesium salt
(1) Solutions of magnesium salts yield upon warming with ammonium carbonate TS a white precipitate, which dissolves in ammonium chloride TS. A white, crystalline precipitate is reproduced by subsequent addition of disodium hydrogen phosphate TS.
(2) Solutions of magnesium salts yield a white, gelatinous precipitate with sodium hydroxide TS. When iodine TS is added to one portion of the suspension suspension, the precipitate develops a dark-brown color. When excess sodium hydroxide TS is added to another portion, the precipitate does not dissolve.

Manganese salt
(1) Solutions of manganese salts yield a white precipitate with ammonia TS. When silver nitrate TS is added to a portion of the suspension, the precipitate changes to black. When another portion is allowed to stand, the upper part of the precipitate exhibits a brownish color.
(2) Acidic solutions of manganese salts in dilute nitric acid exhibit a purple-red color with a small quantity of powdered sodium bismuthate.

 

Mercuric salt
(1) A copper plate is immersed in solutions of mercuric salts, allowed to stand, taken out, and then washed with water. The plate becomes bright and silvery white in appearance, when rubbed with paper or cloth (common with mercurous salts).
(2) Solutions of mercuric salts yield a black precipitate with a small quantity of sodium sulfide TS. The precipitate dissolves in an excess of the reagent. The black precipitate is reproduced by subsequent addition of ammonium chloride TS.
(3) When potassium iodide TS is added drop-wise to neutral solutions of mercuric salts, a red precipitate is produced. The precipitate dissolves in an excess of the reagent.
(4) Acidic solutions of mercric salts in hydrochloric acid yield a white precipitate with a small quantity of stannous chloride TS. The precipitate changes to grayish black upon addition of an excess of the reagent.

 

Mercurous salt
(1) A copper plate is immersed in solutions of mercurous salts, allowed to stand, taken out, and then washed with water. The plate becomes bright and silvery white in appearance, when rubbed with paper or cloth (common with mercuric salts).
(2) Mercurous salts or their solutions exhibit a black color with sodium hydroxide TS.
(3) Solutions of mercurous salts yield a white precipitate with dilute hydrochloric acid. The separated precipitate changes to black upon addition of ammonia TS.
(4) Solutions of mercurous salts yield a yellow precipitate with potassium iodide TS. The precipitate changes to green, when allowed to stand, and changes again to black upon subsequent addition of an excess of the reagent.

Mesilate
(1) To mesilates add twice its mass of sodium hydroxide, heat gently to melt, and continue heating for 20 to 30 seconds. After cooling, add a little amount of water, then add dilute hyudrocholric acid, and warm: the gas evolved changes moistened potassium iodatestarch paper to blue.

(2) To mesilates add threefold its mass of sodium nitrate and anhydrous sodium carbonate, mix, and heat gradually. After cooling, dissolve the residue in diluted hydrochloric acid (1 in 5), and filter if necessary. The filtrate yields a white precipitate upon addition of barium chloride TS.

Nitrate
(1) When a solution of nitrates is mixed with an equal volume of sulfuric acid, the mixture is cooled, and ferrous sulfate TS is superimposed, a dark-brown ring is produced at the junction of the two liquids.

(2) Solutions of nitrates exhibit a blue color with diphenylamine TS.
(3) When potassium permanganate TS is added to acidic solutions of nitrates in sulfuric acid, the redpurple color of the reagent does not fade (discrimination from nitrites).

Nitrite
(1) Solutions of nitrites, when acidified with dilute sulfuric acid, evolve a yellow-brown gas with a characteristic odor. The solutions exhibit a dark-brown color upon addition of a small quantity of iron (II) sulfate heptahydrate crystals.
(2) Solutions of nitrites, when 2 to 3 drops of potassium iodide TS and dilute sulfuric acid are added drop-wise, exhibit a yellow-brown color, and then yield a black-purple precipitate. When the mixture is shaken with 2mL of chloroform, the chloroform layer exhibits a purple color.
(3) Solutions of nitrites, when mixed with thiourea TS and acidified with dilute sulfuric acid, and iron(III)chloride TS is added drop-wise, exhibit a dark red color. When the mixture is shaken with 2mL of ether, the ether layer exhibits a red color.

 

Oxalate
(1) When potassium permanganate TS is added drop-wise to warm acidic solutions of oxalates in sulfuric acid, the reagent is decolorized.
(2) Solutions of oxalates yield a white precipitate with calcium chloride TS. The separated precipitate does not dissolve in dilute acetic acid but dissolves upon subsequent addition of dilute hydrochloric acid.

Permanganate
(1) Solutions of permanganates exhibit a redpurple color.
(2) When an excess of hydrogen peroxide TS is added to acidic solutions of permanganates in sulfuric acid, the solutions effervesce and decolorize permanganates.
(3) Acidic solutions of permanganates in sulfuric acid are decolorized, when an excess of oxalic acid TS is added and heated.

Peroxide
(1) Solutions of peroxides are mixed with an equal volume of ethyl acetate and 1 to 2 drops of potassium dichromate TS, and then acidified with dilute sulfuric acid. When the mixture is shaken immediately and allowed to stand, the ethyl acetate layer exhibits a blue color.
(2) Acidic solutions of peroxides in sulfuric acid decolorize potassium permanganate TS, added dropwise, and effervesce to evolve a gas.

Phosphate (Orthophospbate)
(1) Neutral solutions of phosphates yield a yellow precipitate with silver nitrate TS. The precipitate dissolves upon addition of dilute nitric acid or ammonia TS.
(2) Neutral solutions or acidic solutions in dilute nitric acid of phosphates yield a yellow precipitate with ammonium molybdate TS on warming. The precipitate dissolves upon subsequent addition of sodium hydroxide TS or ammonia TS.
(3) Neutral or ammonia-alkaline solutions of phosphates yield a white, crystalline precipitate with magnesia TS. The precipitate dissolves upon subsequent addition of dilute hydrochloric acid.

Potassium salt
(1) When the Flame Coloration Test (1) is applied to potassium salts, a pale purple color develops. When it gives a yellow color, a red-purple color can be seen through cobalt glass.
(2) Neutral solutions of potassium salts yield a white, crystalline precipitate with sodium bitartrate TS. The formation of the precipitate is accelerated by rubbing the inside wall of the test tube with a glass rod. The separated precipitate dissolves upon addition of any of ammonia TS, sodium hydroxide TS or sodium carbonate TS.
(3) Acidic solutions of potassium salts in acetic acid yield a yellow precipitate with sodium cobalt nitrite TS.

(4) Potassium salts do not evolve the odor of ammonia, when an excess of sodium hydroxide TS is added and warmed (discrimination from ammonium salts).

 

Salicylate
(1) Salicylates evolve the odor of phenol, when an excess of soda-lime is added and heated.
(2) Concentrated solutions of salicylates yield a white, crystalline precipitate with dilute hydrochloric acid. The separated precipitate, washed well with cold water and dried, melts at about 159 °C.
(3) Neutral solutions of salicylates exhibit with 5 to 6 drops of dilute iron (III) chloride TS a red color, which changes to purple and then fades when dilute hydrochloric acid is added drop-wise.

Silver salt
(1) Solutions of silver salts yield a white precipitate with dilute hydrochloric acid. When dilute nitric acid is added subsequently to a portion of the suspension, the precipitate does not dissolve. When an excess of ammonia TS is added to another portion, the precipitate dissolves.
(2) Solutions of silver salts yield a red precipitate with potassium chromate TS. The precipitate dissolves upon addition of dilute nitric acid.
(3) Solutions of silver salts yield a brownish gray precipitate with ammonia TS added drop-wise. When ammonia TS is added drop-wise until the precipitate dissolves, then 1 to 2 drops of formaldehyde solution are added and warmed, a mirror of metallic silver is deposited on the inside wall of the container.

Sodium salt
(1) When the Flame Coloration Test (1) is applied to sodium salts, a yellow color develops.
(2) Concentrated, neutral or slightly alkaline solutions of sodium salts yield a white, crystalline precipitate with potassium hexahydroxoantimonate(V) TS. The formation of the precipitate is accelerated by rubbing the inside wall of the test tube with a glass rod.

 

Stannic salt
(1) When the outside bottom of a test tube containing water is moistened with acidic solutions of stannic salts in hydrochloric acid and is placed in a non-luminous flame of a Bunsen burner, a blue flame mantle is seen around the bottom of the test tube (common with stannous salts).
(2) When granular zinc is immersed in acidic solutions of stannic salts in hydrochloric acid, a spongy, gray substance is deposited on the surface of the granules (common with stannous salts).
(3) Add iron powder to acidic solutions of stannic salts in hydrochloric acid, allow to stand, and then filter. When iodine-starch TS is added drop-wise to the filtrate, the color of the test solution disappears.
(4) Acidic solutions of stannic salts in hydrochloric acid, to which ammonia TS is added drop-wise until a small quantity of precipitate is produced, yield a pale yellow precipitate with 2 to 3 drops of sodium sulfide TS. The separated precipitate dissolves upon addition of sodium sulfide TS and pale yellow precipitate is reproduced by subsequent addition of hydrochloric acid.

 

Stannous salt
(1) When the outside bottom of a test tube containing water is moistened with acidic solutions of stannous salts in hydrochloric acid and is placed in a non-luminous flame of a Bunsen burner, a blue flame mantle is seen around the bottom of the test tube (common with stannic salts).
(2) When granular zinc is immersed in acidic solutions of stannous salts in hydrochloric acid, a spongy, gray substance is deposited on the surface of the granules (common with stannic salts).
(3) When iodine-starch TS is added drop-wise to solutions of stannous salts, the color of the test solution disappears.

(4) Acidic solutions of stannous salts in hydrochloric acid, to which ammonia TS is added drop-wise until a small quantity of precipitate is produced, yield a dark brown precipitate with 2 to 3 drops of sodium sulfide TS. When sodium sulfide TS is added to a portion of the separated precipitate, it does not dissolve. When ammonium polysulfide TS is added to another portion, the precipitate dissolves.

Sulfate
(1) Solutions of sulfates yield a white precipitate with barium chloride TS. The precipitate does not dissolve upon addition of dilute nitric acid.

(2) Neutral solutions of sulfates yield a white precipitate with lead acetate TS. The precipitate dissolves upon subsequent addition of ammonium acetate TS.
(3) When an equal volume of dilute hydrochloric acid is added, solutions of sulfates yield no white turbidity (discrimination from thiosulfates), and do not evolve the odor of sulfur dioxide (discrimination from sulfites).

Sulfide
Most kinds of sulfides evolve the odor of hydrogen sulfide with dilute hydrochloric acid. This gas blackens lead acetate paper moistened with water.

 

Sulfite and Bisulfite
(1) When iodine TS is added drop-wise to acidic solutions of sulfites or bisulfites in acetic acid, the color of the reagent fades.
(2) When an equal volume of dilute hydrochloric acid is added, solutions of sulfites or bisulfites evolve the odor of sulfur dioxide but yield no turbidity (discrimination from thiosulfates). The solutions yield immediately with 1 drop of sodium sulfide TS a white turbidity, which changes gradually to a pale yellow precipitate.

 

Tartrate
(1) Neutral tartrate solutions yield a white precipitate with silver nitrate TS. When nitric acid is added to a portion of the separated precipitate, it dissolves. When ammonia TS is added to another portion and warmed, the precipitate dissolves and metallic silver is deposited gradually on the inside wall of the test tube, forming a mirror.
(2) Solutions of tartrates exhibit a red-purple to purple color, when 2 drops of acetic acid(31), 1 drop of iron (II) sulfate TS, 2 to 3 drops of hydrogen peroxide TS and an excess of sodium hydroxide TS are added.

(3) When a solution, prepared by mixing 2 to 3 drops of resorcinol solution (1 in 50) and 2 to 3 drops of potassium bromide solution (1 in 10) with 5mL of sulfuric acid, is added to 2 to 3 drops of solutions of tartrates, and then heated for 5 to 10 minutes on a water- bath, a deep blue color is produced. The solution exhibits a red to red-orange color when poured to 3mL of water after cooling.

 

Thiocyanate
(1) Solutions of thiocyanates yield a white precipitate with an excess of silver nitrate TS. When dilute nitric acid is added to a portion of the suspension, the precipitate does not dissolve. When strong ammonia water is added to another portion, the precipitate dissolves.
(2) Solutions of thiocyanates produce a red color with iron(III)chloride TS. The color does not disappear by addition of hydrochloric acid.

 

Thiosulfate
(1) When iodine TS is added drop-wise to acidic solutions of thiosulfates in acetic acid, the color of the reagent fades.
(2) When an equal volume of dilute hydrochloric acid is added, solutions of thiosulfates evolve the odor of sulfur dioxide, and yield gradually a white turbidity, which changes to yellow on standing.
(3) Solutions of thiosulfates yield a white precipitate with an excess of silver nitrate TS. The precipitate changes to black on standing.

Zinc salt
(1) Neutral to alkaline solutions of zinc salts yield a whitish precipitate with ammonium sulfide TS or sodium sulfide TS. The separated precipitate does not dissolve in dilute acetic acid but dissolves upon subsequent addition of dilute hydrochloric acid.
(2) Solutions of zinc salts yield a white precipitate with potassium hexacyano ferrate (II) TS.. When dilute hydrochloric acid is added to a portion of the suspension, the precipitate does not dissolve. When sodium hydroxide TS is added to another portion, the precipitate dissolves.
(3) Neutral to weakly acidic solutions of zinc salts yield a white precipitate, when 1 or 2 drops of pyridine and 1mL of potassium thiocyanate TS are added.