221
I N D U S T R I A L A N D ENGINEERING CHEMIXTRY
April 15, 1931
the grips has been entirely overcome, otherwise there would be a larger spread between the individual curves for the test pieces from a given sample. Of course, variations in the cross section of the test pieces will prevent coincidence of the separate stress-strain curves, but when the proper corrections have been made, the calculated points show close agreement. Figure 4 is a comparison of the curves obtained for single
threads using this machine, and for dumb-bell-shaped test pieces cut from the same sheet and tested in the regular fashion with the Scott rubber tester. On account of the great differences in geometrical configuration of the two types of test pieces and in the rate of loading, it is to be expected that there will be appreciable differences in the stress-strain curves, such as are indicated here in the region of higher elongations.
Recommended Specifications for Analytical Reagent Chemicals’ Perchloric Acid 40 Per Cent, Cadmium Chloride (CdC12.21/2H,0),Chromium Trioxide, Lead Chromate, Lead Nitrate, Magnesium Oxide, Mercuric Chloride, Mercurous Chloride, Sodium Nitroferricyanide, Uranium Nitrate W. D. Collins, Gregory P. Baxter, H. V. Farr, J. V. Freeman, Joseph Rosin, G . C. Spencer, a n d Edward Wichers COMMITTEE ON ANALYTICAL REAGENTS, AMERICAN CHEMICAL SOCIETY
T
HE specifications given below are intended t o serve for reagents t o be used in careful analytical work. The limits and tests are based on published work, on the experience of members of the committee in the examination of reagent chemicals on the market, and on studies of the tests made by members of the committee as the various items were considered. Suggestions for improvement of the specifications will be welcomed by the committee. In all the directions the acids and ammonium hydroxide referred to are of full strength unless dilution is specified; dilution indicated as (1 3) means 1 volume of the reagent or strong solution with 3 volumes of water; “water” means distilled water of a grade suitable for the test described; reagents used in making the tests are supposed to be of the grade recommended below or in previous publications ( I , 2, 3, 4, 5, 6, 7) from the committee. Directions for the preparation of the ammonium molybdate solution are given under the test for phosphate in ammonium nitrate (3). A time of 5 minutes is t o be allowed for the appearance of precipitates and before observation of color reactions, unless some other time is specified. Blank tests must be made on water and all reagents used in the tests unless the directions provide for elimination of errors due t o impyities. Solutions of samples must be filtered for tests in which insoluble matter would interfere.
+
Acid, Perchloric-60
Per C e n t
REQUIREMENTS Assay-Sot less than 59 per cent HClOa. Non-Volatzle Matter-Sot more than 0.015 per cent. Chloride (Cl)-Not more than 0 001 per cent, Nitrogen Compounds (as N)-Sot more than 0.004 per cent. Sulfate (Sod)-Not more than 0.005 per cent. Ammonia (“a)-Not more than 0.001 per cent. Heavy Metals-To pass test (limit about 0.0005 per cent’lead). Iron (Fe)-Sot more than 0 0002 per cent.
TESTS Assay-Titrate a weighed portion of the acid, after suitable dilution, with standard alkali hydroxide solution, using phenolphthalein as indicator. Non-Volatile Matter-Evaporate 9 cc. of the acid and ignite gently. T h e residue should not weigh more than 0.0015 gram. Chloride-Dilute 5 cc. with 40 cc. of water, add 3 cc. of nitric acid and 1 cc. of 0.1 N silver nitrate. The turbidity should not be greater than is produced by 0.05 mg. of chloride ion in the same volume of a solution containing t h e quantities of nitric acid and silver nitrate used in the test. 1 Received March 6, 1931. Presented in connection with the report of the Committee on Analytical Reagents a t the 81st Meeting of the American Chemical Society, Indianapolis, Ind., March 30 t o April 3, 1931.
Nitrogen Compounds-Dilute 1 cc. of the sample in a flask with 10 cc. of ammonia-free water, add 10 cc. of 10 per cent sodium hydroxide solution and about 0.5 gram of aluminum wire in small pieces, and allow t o stand for 3 hours protected from loss or absorption of ammonia. Dilute to 60 cc., decant from any insoluhle matter, and add 2 cc. of Nessler’s reagent. The color should not be greater than is produced by 0 04 mg. of N as NHs in the same volume of a solution containing the quantities of sodium hydroxide and Sessler’s reagent used in the test. SuZfale-Dilute 10 cc. of the acid with 35 cc. of water and neutralize with ammonium hydroxide, using litmus paper as indicator. Add 0.5 CC. of dilute hydrochloric acid (1 part strong acid in 10) and 5 cc. of 10 per cent barium chloride solution, and allow to stand overnight. Any precipitate of barium sulfate should not weigh more than 0.0012 gram. Cor. rection should be made for the weight obtained on running a blank, including filtsation, using the quantities of reagents used in the test. Most of the ammonia should be removed by evaporation so t h a t only a small quantity of acid will be required for neutralization before acidifying for the precipitation. Ylmmonia-Dilute 2 cc. of the sample with 40 cc. of ammonia-free water, add 10 cc. of 10 per cent sodium hydroxide solution and 2 cc. of Nessler’s reagent, Any yellow color produced should not be greater than is given by 0.02 mg. of NH.2 in the same volume of a solution containing the quantities of sodium hydroxide and Nessler’s reagent used in the test. Heavy Metals, Iron-Dilute 5 cc. with 40 cc. of water, add 5 cc. of hydrogen sulfide water, and make alkaline with ammonium hydroxide. S o brown color should be observed. Any greenish color should not be greater than is produced by 0.01 mg. of iron in an equal volume of alkaline sulfide solution.
C a d m i u m Chloride (CdC12.21/zHz0) REQUIREMENTS Insoluble Matt%-Sot more than 0.005 per cent, Nitrate (N0a)-To pass test (limit about 0 003 per cent). Sulfate (SO4)-Sot more than 0.005 per cent. Ammonia (NHa)-Sot more than 0.005 per cent. Copper (Cu)-To pass test (limit about 0.0005 per cent). Iron (Fe)-To pass test (limit about 0.001 per cent). Lead (Pb)-To pass test (limit about 0 005 per cent). Substances Not Precipitated by Ammonium Suljde-Sot more than 0.2 per cent. Zinc (2n)-To pass test (limit about 0.05 per cent).
TESTS Insoluble Matter-Dissolve 10 grams in 50 cc. of hot water and heat on the steam bath for 1 hour. Filter through asbestos in a Gooch crucible, wash thoroughly, dry a t 105” to 110’ C., and weigh. The weight of the insoluble residue should not exceed 0.0005 gram. Nitrate-To a solution of 2 grams in 10 cc. of water add 10 cc. of sulfuric acid and 2 drops of indigo solution (1 in 1000). The blue color should not disappear in 10 minutes. Sulfate-Heat to boiling the filtrate and washings obtained in the test for insoluble matter (which should measure not more than about 150 cc,), add 1 cc. of 1 N hydrochloric acid and 5 cc. of 10 per cent barium chloride solution and allow t o stand overnight. Filter, wash thoroughly, and ignite. The weight of the barium sulfate shovld not he more than 0.0012 g r a p
ANALYTICAL EDITION
222
Correction must be made for a blank test made with the same quantities of reagents and including the filtration and ignition of t h e paper. Ammonia-Dissolve 2 grams in 75 cc. of water and add with stirring 25 cc. of a cold 10 per cent solution of sodium hydroxide. After allowing the precipitate t o subside, decant 50 cc. of the clear liquid and add 2 cc. of Nessler's solution. Any coloration produced should not be greater than is produced by 0.05 mg. of NH3 under the same conditions. Copper and Iron-Dissolve 1 gram in 20 cc. of water, add 2 drops of *nitric acid, bring to a boil, and allow to cool. Add 2 drops of a 10 per cent solution of potassium ferrocyanide and stir well. The precipitate formed should not have a red or blue tint after standing 15 minutes. Lead-Dissolve 1 gram in 25 cc. of water, add 5 drops of glacial acetic acid, and filter if necessary. Add 1 cc. of 1 per cent potassium chromate solution. Any turbidity or precipitate should not be greater than is produced by 0.05 mg. of lead under the same conditions. Substances Not Precipitated by Ammoninm Sulfide-Dissolve 2 grams in I50 cc. of water, add ammonium hydroxide t o dissolve the precipitate first formed, and pass hydrogen sulfide gas through the solution to precipitate all the cadmium. Filter off 75 cc. of the clear liquid, add 5 drops of sulfuric acid, evaporate to dryness, and ignite gently. The weight of the ignited residue should not be more than 0.0020 gram. Zinc-Dissolve 0.2gram in 100 cc. of water and add 3.5 cc. of sulfuric acid. Heat to boiling and pass a rapid stream of hydrogen sulfide for 15 minutes, allowing the solution to cool during the passage of the gas. Filter at once, evaporate the filtrate and expel practically all of t h e sulfuric acid. Take up the residue with 5 cc. of water and add ammonium hydroxide until the solution is just alkaline t o litmus paper. Then make i t just acid to the litmus paper with 0.1 N sulfuric acid. Dilute to 100 cc. and pass a rapid stream of hydrogen sulfide for 5 minutes, N o white precipitate or turbidity should be produced.
Chromium Trioxide REQu IR EM EN Ts Assay-Not less than 96 per cent. Insoluble Matter-Not more than 0.010 per cent. Chloride (C1)-To pass test (limit about 0.005 per cent). Sulfate (SO&-Not more than 0.005 per cent. Alkali Salts-Not more than 0.2per cent. Iron, Aluminum, Barium, Etc.-Not more than 0.03 per cent.
Vol. 3, No. 2
and dilute to 20 cc. Make the solution barely al-kline with sodium peroxide, boil for 6 minutes, acidify with dilute sulfuric acid, add a slight excess of ammonium hydroxide, boil for 5 minutes, filter, wash, ignite, and weigh. The weight of the ignited precipitate should not exceed 0.0015 gram.
Lead Chromate REQUIREMENTS Assay-Not less than 98 per cent PbCrOa. Soluble Matter-Not more than 0.20 per cent. Carbon Compounds (as C)-Not more than 0.003 per cent. TESTS Assay-Dissolve 0.5 gram of the powdered sample by warming with 20 cc. of 20 per cent sodium hydroxide solution in a glass-stoppered 250-cc. bottle. Add 2 grams of potassium iodide and when i t has dissolved, dilute with 100 cc. of water and add 15 cc. of hydrochloric acid. Allow to stand, protected from light, for 5 minutes. Then titrate the liberated iodine with 0.1 N thiosulfate, adding starch solution towards t h e end. Each cubic centimeter of thiosulfate corresponds t o 0.01077 gram PbCr04. Note-There are on the market several basic lead chromates of variable composition. The object of the assay is t o insure for reagent purposes, a uniform normal chromate. Moreover, by adoptihg an assav, the testing for impurities such as chloride, sulfate, etc., which is rather difficult in this instance, can be dispensed with. Soluble Matter-Boil about 0.5 gram of the powdered sample for 5 minutes with a mixture of 100 cc. of water and 5 cc. of glacial acetic acid, stirring well during the heating. Cool and filter. Evaporate 25 cc. of the filtrate t o dryness on the steam bath and dry a t 105' to 110' C. Heat 50 cc. of the filtrate with 2 grams of the powdered sample for 5 minutes a t 80' t o 90' C., cool, dilute to 50 cc., and filter. Evaporate 25 cc of this filtrate on the steam bath and dry a t 105" t o 110' C. The difference between the weights of the two residues should not be more than 0.0020 gram. Carbon Compounds-Heat 4 grams in a stream of carbon dioxide-free air or oxygen in a combustion tube and pass the evolved gas through 10 CC. of saturated barium hydroxide solution diluted t o 50 cc. The turbidity should not be greater than is produced in a similar solution of barium hydroxide by 2 cc. of 0.01 N sodium carbonate solution
Lead Nitrate
TESTS REQUIREXENTS Assay-Dissolve 5 grams in water, make up to 1000 cc. and mix well. Transfer 25 cc of the solution to a glass-stoppered bottle and dilute with 100 cc. of water. Add 5 cc. of hydrochloric acid and 3 grams of potassium iodide and allow to stand in the dark for 15 minutes. Dilute with another 100 cc. of water and titrate the liberated iodine with 0.1 N sodium thiosulfate solution, adding a little starch towards the end. Correct for the thiosulfate consumed in a blank test made with the same quantities of reagents. Insoluble Matter-Dissolve 10 grams in 100 cc. of water, and allow to stand on the steam bath for 1 hour. Filter through asbestos in a Gooch crucible, wash thoroughly, dry at 105" to 110' C.,and weigh The weight of the insoluble residue should not exceed 0.0010 gram. Chloride-Dissolve 1 gram in 20 cc. of water, add 10 cc. of nitric acid, heat to about 50" C., and add a few drops of 0.1 N silver nitrate solution. No turbidity should be produced in 5 minutes. Sulfate-Dissolve 10 grams in 350 cc. of water and add 5 grams of sodium carbonate. Heat to boiling and add 35 cc. of a solution containing l gram of barium chloride and 2 cc. of hydrochloric aci? per 100 cc. of solution. Digest on the steam bath for 2 hours and allow to stand a t room temperature overnight. If any precipitate forms, filter, wash, and ignite it. Fuse the residue with 1 gram of sodium carbonate. Extract the fused mass with water and filter off the insoluble residue. Add 5 cc of hydrochloric acid to the filtrate, dilute to about 200 cc., heat t o boiling, and add 10 cc. of alcohol Digest on the steam bath until reduction of chromate is complete as indicated by the change to a clear green or colorless solution. Neutralize the solution with ammonium hydroxide and add 2 cc. of hydrochloric acid Heat to boiling and add 10 cc of a 10 per cent solution of barium chloride. Digest on t h e steam bath for 2 hours and allow to stand overnight. Filter, ignite, and weigh. Correction must be made for a blank determination on the reagents, including filtration and ignition of t h e filter paper. Alkali Salts-Carefully ignite 0.5 gram in a porcelain dish until decomposed Cool thoroughly, triturate well the residue with 10 cc. of hot water, filter through a small filter paper, and wash with about 25 cc. of hot water. Evaporate the filtrate and washings to dryness in a small porcelain dish, and ignite Warm the residue with 10 cc. of water, filter, and wash with small quantities of hot water until the washings are colorless. Evaporate t h e filtrate and washings to dryness, ignite gently, and weigh. The weight of the residue should not exceed 0 0010 gram. Iron, Aluminum, Barium, Etc.-Dissolve 5 grams in 100 cc. of water, heat, add 10 cc. of ammonium hydroxide, and boil for 5 minutes. Filter, dissolve the precipitate in warm dilute hydrochloric acid (1 l ) , wash,
+
Insoluble Matter-Not more than 0.005 per cent. Chloride (Cl)-Not more than 0.001 per cent. Copper (Cu)-To pass test (limit about 0.002 per cent). Iron (Fe)-Not more than 0.001 per cent. Substances Not Precipitated by Hydrogen Sulfide (as sulfated-Not than 0.10 per cent. '
more
TESTS insoluble &'alter-Dissolve 10 grams in 100 cc. of water and allow to stand on the steam bath for 1 hour. Filter through asbestos in a Gooch crucible, wash thoroughly, dry a t 105O to l l O a C., and weigh. The weight of t h e insoluble residue should not exceed 0.0005gram. Chloride-To a solution of 2 grams in 10 cc. of water, add 5 drops of nitric acid and 1 cc. of 0.1 A' silver nitrate solution. Any turbidity produced should not be greater than is produced by 0.02 mg. of chloride ion under the same conditions. Copper and Iron-Dissolve 5 grams in about 40 cc. of water, add 5 cc. of sulfuric acid, evaporate, and heat until fumes of SOa are evolved. Cool, mix with about 50 cc. of water, and filter. Wash the precipitate with 15 to 20 cc. of water. Cool the filtrate and divide into two equal portions. Copper-Bring one-half of t h e filtrate to a boil, add a slight excess of ammonium hydroxide, and filter. Acidify the filtrate with acetic acid and add 2 cc. of freshly prepared 10 per cent solution of potassium ferrocyanide. No red color should be produced in 10 minutes. Iron-To the second half of the filtrate, add 2 cc. of hydrochloric acid and 3 cc. of a 10 per cent solution of ammonium thiocyanate. Any red color produced should not be greater than is produced by 0.025 mg. of iron urfder the same conditions. Substances Not Precipitated by Hydrogen Sulfide-Dissolve 2 grams in 100 cc. of water and pass hydrogen sulfide through the solution to precipitate the lead completely. Filter, but do not wash. To 50 cc. of the filtrate, ,add 5 drops of sulfuric acid, evaporate to dryness, and ignite. The weight of the ignited residue should not exceed 0.0010 gram.
Magnesium Oxide REQUIREMENTS insoluble in Hydrochloric Acid-Not more than 0.030 per cent. Silica (SO*)-Not more than 0.020 per cent. Animonium Hydroxide Precipitate-Not more than 0.02b per cent.
I N D U X T R l A L &4il'DENGINEERING CHEMISTRY
April 15, 1931
Chloride ((21)-Not more than 0.010 per cent. Nitrate (NOa)-To pass test (limit about 0.005 per cent). Sulfate and Sulpte (so4and S0a)-Not more than 0,010 per cent as SOi. Barium (Ba)-To pass test (limit about 0.005 per cent). Calcium (Ca)-To pass test (limit about 0.05 per cent). Heavy Metals (as Pb)-Not more than 0.005 per cent. Ammonium Sulfide Metals (as Fe)--Not more than 0.01 per cent. Soluble in Water-Not more than 0.50 per cent. Loss on Ignition-Not more than 10 per cent. TE5TS Insoluble i n Hydrochloric Acid-Dissolve 5 grams in 100 cc. of water and 26 cc. of hydrochloric acid. Boil for 6 minutes, filter through asbestos in a Gooch crucible, wash thoroughly, dry a t 105O t o l l O o C., and weigh. The weight of the residue should not exceed 0.0015 gram. Silica-Neutralize the filtrate from the determination of matter insoluble in hydrochloric acid with ammonium hydroxide, using methyl red a s the indicator, and add 1 cc. in excess. Heat the solution to boiling, boil for a few minutes, and allow t o cool. (This operation precipitates a small fraction of the magnesium and collects all of the silica, as well as the usual R?Oa precipitate.) Filter a n d discard the filtrate. Dissolve the precipitate from the filter paper by dropping over i t hot dilute hydrochloric acid (1 11, finally washing out all soluble salts into the original beaker and retaining any insoluble matter on the filter. Add 5 cc. of sulfuric acid and evaporate the solution to fumes. Cool, dilute with water, and filter through the paper previously used. Wash, ignite, and weigh. Treat the ignited precipitate with a few drops of sulfuric acid and hydrofluoric acid. Evaporate off the hydrofluoric acid, ignite, and weigh. The weight of silica should not exceed 0.0010 gram. Ammonium Hydroxide Precipifate-To the last filtrate from the silica determination add a slight excess of ammonium hydroxide and boil gently in a covered beaker till the excess of ammonia is expelled. Filter, wash thoroughly, and ignite. The weight of the ignited precipitate should not exceed 0.0010 gram. Chloride-Add 0.5 gram of the sample to a mixture of 100 cc. of water and 3 cc. of nitric acid. Filter if necessary, dilute to 25 cc., and add 1 cc. of 0.1 N silver nitrate solution. Any turbidity produced should not be greater than is produced by 0.05 mg. of chloride in an equal volume of solution containing the quantities of reagents used in the test. Nitrate-In-a mixture of 1 gram of the sample and 15 cc. of water, dissolve 50 mg. of sodium chloride, add 2 drops of indigo solution (1in 1000) and add slowly with constant stirring 15 cc. of sulfuric acid. The color should not be destroyed in 5 minutes. Sulfate and Suljite-Moisten 10 grams with 50 cc. of water and dissolve by adding 45 cc. of hydrochloric acid and boiling. Filter and neutralize the filtrate with ammonium hydroxide, using methyl red as indicator. Dilute to 200 cc., add 5 drops of bromine water and 2 cc. of hydrochloric acid. Heat to boiling, add 20 cc. of 10 per cent barium chloride solution. Heat on the steam bath 3 or 4 hours, and set aside for 36 hours. Filter, wash thoroughly, ignite, and weigh. The weight of the ignited precipitate should not be more than 0.0025 gram greater than the precipitate obtained by running a blank, including filtration, using the quantities of reagents used in the test. Most of the hydrochloric acid in the blank should be removed by evaporation before neutralization with ammonium hydroxide. Barium-Dissolve 2 grams in a mixture of 16 cc. of water and 10 cc. of hydrochloric acid, and filter. T o one-half the filtrate add 1 cc. of N sulfuric acid. There should be no difference in turbidity of the two portions a t the end of 30 minutes. Calcium-Mix 1 gram with 4 cc. of water and add hydrochloric acid drop by drop till the oxide is just dissolved. Dilute with water to 10 cc. and filter if necessary. Mix 5 cc. of the solution with 50 cc. of 95 per cent alcohol, add 20 cc. of dilute sulfuric acid (1 a), and allow to stand overnight. No precipitate or turbidity should be produced. If crystals are formed warm the solution slightly. Heavy Metals-Mix 1 gram with 20 cc. of water and add hydrochloric acid (about 5 cc.) until the oxide is dissolved. Neutralize to litmus paper with ammonium hydroxide. Add 3 drops of glacial acetic acid, dilute to 50 cc., and pass hydrogen sulfide through the solution. Any dark color produced should not be greater than is produced by 0.05 mg. of lead in a solution of the same acidity containing the quantities of reagents used in t h e test. Ammonium Sulfide Netals-Moisten 1 gram with 20 cc. of water, add 5 cc. of hydrochloric acid, and heat until the oxide is dissolved. Make t h e solution alkaline to litmus paper with ammonium hydroxide, and add 5 cc. of hydrogen sulfide water. Any green or brown color should not be deeper than the green color produced by 0.10 mg. of iron in an alkaline sulfide solution. Soluble in Water-Heat to boiling 2 grams of the sample With 50 cc. of water and filter while hot. Evaporate 25 cc. of the filtrate t o dryness on the water bath and ignite gently. The weight of the residue should not exceed 0.0050 gram. Loss on Ignition-Ignite about 0.25 gram in a covered platinum crucible a t a bright red heat for 15 minutes. The loss should correspond to not more than 10 per cent.
+
+
223
Mercuric Chloride REQUIREMENTS Non-Volatile Matter-Not more than 0.020 per cent. Solution in Ether-To pass test. Iron (Fe)-Not more than 0.002 per cent.
TESTS Non-Volatile Matter-Ignite 5 grams with 1 cc. of sulfuric acid. The weight of the residue should not exceed 0.0010 gram. Solution in Ether-Two grams of mercuric chloride should dissolve in 60 cc. of ether without leaving an insoluble residue. Iron-Dissolve the residue obtained in the test for non-volatile matter by warming with 1 cc. of hydrochloric acid. Dilute with 20 cc. of water, akid 2 cc. of hydrochloric acid and 2 cc. of 10 per cent ammonium thiocyanate solution. The red color should not be more than is produced by 0.1 mg. of ferric iron under the same conditions.
Mercurous Chloride REQUIREMENTS Non-Volatile Matter-Not more than 0.020 per cent. Mercuric Chloride (HgC1z)-Not more than 0.01 per cent. Sulfate (SOa)-Not more than 0.01 per cent.
TESTS Nan-Volatile-Ignite 5 grams with 1 cc. of sulfuric acid. The weight of the residue should not exceed 0.0010 gram. Mercuric Chloride-Shake 1 gram with 10 cc. of alcohol for 5 minutes, and filter. T o 5 cc. of the filtrate, add 2 drops of hydrochloric acid and 5 cc. of hydrogen sulfide water. Any darkening produced should not be greater than is produced by 0.05 mg. of mercuric chloride in a mixture of 5 cc. of alcohol, 2 drops of hydrochloric acid, and 5 cc. of hydrogen sulfide water. Sulfate-Digest 2 grams for 10 minutes with 20 cc. of a mixture of equal volumes of hydrochloric acid and water. Filter, add 0.01 gram of sodium carbonate to one-half of the filtrate, and evaporate t o dryness on the steam bath. Treat the residue with 0.5 cc. of dilute hydrochloric acid (1 f 4), dilute t o 10 cc., and add 0 . 5 of 10 per cent barium chloride solution. Any turbidity should not be greater than is produced by 0.1 mg. of SO4 under the same conditions.
Sodium Nitroferricyaqide REQUIREMENTS Insoluble Matter-Not more than 0.010 per cent. Chloride (Cl)-Not more than 0.030 per cent. Sulfate (SOd)-To pass test (limit about 0.01 per cent).
TESTS Insoluble Matter-Dissolve 5 grams in 50 cc. of water and allow to stand on the steam hath for 1 hour. Filter through asbestos in a Gooch crucible, wash thoroughly, dry at 105' t o 110' C., and weigh. The weight of the insoluble residue should not exceed 0.0005 gram. Chloride-Dissolve 2 grams in 175 cc. of water, add 2.5 grams of copper sulfate crystals (free from chloride) dissolved in 25 cc. of water, mix thoroughly, allow to stand till the precipitate has settled and filter, rejecting the first part of the filtrate. T o 10 cc. of the filtrate, add 2 cc. of nitric acid and 1 cc. of 0.1 N silver nitrate solution. Any turbidity should not b e greater than is produced by 0.03 mg. of chloride under the same conditions. Sulfate-Dissolve 6 grams in 100 cc. of water without heating, filter, and to the filtrate add 5 drops of glacial acetic acid and 5 cc. of 10 per cent barium chloride solution. Stir and pour into a Nessler tube for observation. No turbidity should be produced in 10 minutes.
Uranium Nitrate REQUIREMEKTS Insoluble Matter-Not more than 0.010 per cent. Chloride (C1)-Not more than 0.002 per cent. Sulfate (Sod)-To pass test (limit about 0.005 per cent). Alkalies and Alkaline Earths (as sulfates)-Not more than 0.10 per cent. Heavy Metals-To pass test (limit about 0.002 per cent Pb). Iron (Fe)--Not more than 0.003 per cent. Uranous Uranium (U'")-Not more than 0.0130per cent. TESTS Insoluble rldatfer-Dissolve 10 grams in 100 cc. of water and heat on the steam bath for 1 hour. Filter through asbestos in a Gooch crucible, wash thoroughly, dry a t 105" to 110' C., and weigh. The weight of the residue should not exceed 0.0010 gram.
A N A L Y TIC.AL EDITION
224
Chloride-Dissolve 1 gram in 20 cc. of water, add 0.5 cc. of nitric acid and 1 cc. of 0.1 N silver nitrate solution. Any turbidity produced should not be greater than is produced by 0.02 mg. of chloride ion upder similar conditions. Sulfate-Dissolve 1 gram in 5 cc of water, add 10 cc. of hydrochloric acid, and evaporate to dryness on the steam bath. Treat the residue with 1cc. of dilute hydrochloric acid (1 f 4) and 10 cc. of water. Filter if neces: sary, and add 1 cc. of 10 per cent barium chloride solution. No turbidity or precipitate should be produced in 15 minutes. Alkalies and Alkaline Earths-Ignite 2 grams until thoroughly decomposed. Powder the cooled residue and boil for 10 minutes with 50 cc. of water. Cool, dilute to 50 cc., mix well, and filter. T o 25 cc. of the filtrate add a few drops of sulfuric acid, evaporate to dryness, and ignite gently. The weight of the residue should not exceed 0.0010 gram. Heavy Metals-Dissolve 2 grams in 5 cc. of water, add 10 cc. of hydrochloric acid, and evaporate t o dryness on the steam bath. Treat the residue with 1 cc. of 0.1 N hydrochloric acid and 20 cc. of water. Filter if necessary and pass hydrogen sulfide through the solution. N o darkening should be observed. Iron-To a solution of 2 grams in 25 cc. of water, add a solution of 5 grams of ammonium thiocyanate in 10 cc. of water and shake the mixture with 10 cc. of ether. The red color produced in the ether should not be greater than is produced by 0.06 mg of iron in a ferric salt treated with the quantities of reagents used in the test. Uranous Uranium-Dissolve 3 grams in 200 cc. of water and add 2 cc. of sulfuric acid. Dissolve and acidify a second equal sample for comparison. Titrate one solution with 0.1 N potassium permanganate. Not more than 0.20 cc. of permanganate should be required t o cause a color change t h a t can be observed by comparison with the solution not titrated. The 0.20 cc. includes 0.05 cc. allowed t o produce the color change in the absence of uranous compounds.
Corrections for Published Specifications Replace the requirements and tests previously printed by the following: G e n e r a l Correction f o r G r a v i m e t r i c D e t e r m i n a t i o n of S u l f a t e I t has been observed in the determination of sulfate in sodium carbonate that the filter paper retains barium and possibly sodium from the solution passed through it, even though the paper is thoroughly washed. The weight of ash obtained when such papers are ignited may exceed 0.5 mg. For this reason a complete blank determination should be made in all cases in which the permitted weight of barium sulfate is small enough to be affected by an error of the magnitude indicated. I n blank determinations in which large amounts of acid are included, as in the case of sodium carbonate, the acidity of the solution should be made to correspond t o t h a t of the solution of the sample by evaporation of the excess of acid. This general provision for blanks on sulfate determinations applies to the following reagents: Citric acid ( 5 ) Oxalic acid (1) Perchloric acid ( 2 ) Phosphoric acid (4) Tartaric acid ( 5 ) Ammonium phosphate (dibasic) ( 3 ) Ammonium thiocyanate (1) Bromine (6) Calcium carbonate (7) Calcium carbonate low in alkalies (7) Calcium chloride (&aClz.2H20) (7) Cupric oxide powdered and granular (6) Cupric oxide’ wire form (7) Cupric a m m h u r n chloride (6) Carbon tetrachloride ( 4 ) Potassium bromate (3) Potassium bromide (3) Potassium carbonate (2)
Potassium chloride ( 2 ) Potassium dichmmate (1) Potassium ferricyanide ( 5 ) Potassium ferrocyanide ( 5 ) Potassium hydroxide (1) Potassium iodate ( 3 ) Potassium iodide (3) Potassium permanganate ( 2 ) Potassium sodium tartrate (6) Sodium acetate ( 3 ) Sodium bicarbonate ( 2 ) Sodium carbonate ( 2 ) Sodium hydroxide ( 1 ) Sodium nitrate ( 4 ) Sodium oxalate ( 1 ) Sodium peroxide (4) Sodium phosphate (dibasic) (4) Zinc chlotide (5)
Acid Phosphoric (4)
TEST Heavy Metals-Dilute 3 cc. with 10 cc. of water and exactly neutralize with ammonium hydroxide, using 3 drops of 1 per cent phenolphthalein solution as indicator. Add 50 cc. of 1 N sulfuric acid and 5 cc. of hydrogen sulfide water, and dilute t o 100 cc. Any brown color which is immediately developed should not be greater than is produced by 0.05 mg. of lead in the same volume of an aqueous solution of a lead salt treated with thelsame amount of hydrogen sulfide water.
Vol. 3, No. 2 B a r i u m C a r b o n a t e (3) REQUIREMENT
Nilrate (NO+-To
pass test (limit about 0.01 per cent).
Nitvate-To 3 grams add 15 cc. of water and 1 drop of indigo solution (1 in IOOO), dissolve by adding 5 cc. of hydrochloric acid, and add with constant stirring 15 cc. of sulfuric acid. The blue color should not be destroyed in 5 minutes. M a g n e s i u m Chloride ( 5 ) REQUIREMENT Barium (Ba)-To
pass test (limit about 0.005 per cent).
Potassium Ferricyanide (5) Potassium Ferrocyanide (5) TESTS Chloride-Instead of filtering, allow the precipitate t o settle in a cylinder and take 50 cc. of the clear supernatant solution for the test with nitric acid and silver nitrate. Sulfate-Omit last two sentences.
Potassium P h o s p h a t e (Monobasic) ( 4 ) TEST Heavy Metals-Dissolve 5 grams in 40 cc. of water and exactly neutralize with ammonium hydroxide using 3 drops of 1 per cent phenolphthalein solution as indicator. Add 40 cc. of N sulfuric acid, 5 cc. of hydrogen sulfide water, and dilute t o 100 cc. Any brown color which is immediately developed should not be greater than is produced by 0.05 mg. of lead in the same volume of an aqueous solution of a lead salt treated with the same amount of hydrogen sulfide water. S o d i u m B i c a r b o n a t e (2)
TEST Calcium, Magnesium, and Ammonium Hydroxide Precipitate-In line 5, replace “Allow t o stand for 3 hours” with “Stir well and allow t o stand overnight.” S o d i u m P h o s p h a t e (Dibasic) (4)
TEST Heavy Metals-Dissolve 5 grams in 40 cc. of water and exactly neutralize the solution with 1 N sulfuric acid, using 3 drops of 1 per cent phenolphthalein solution as indicator. Add 15 cc. of 1 N sulfuric acid and 5 cc. of hydrogen sulfide water, and dilute t o 100 cc. Any brown color which is immediately developed should not be greater than is produced by 0.05 mg. of lead in the same volume of an aqueous solution of a lead salt treated with the same amount of hydrogen sulfide water, S o d i u m T h i o s u l f a t e (2) REQUIREMENT Sulfate and Sulfite-Not
more than 0.10 per cent as
so&
TEST Sulfate and SuZfite-Dissolve 1 gram in 50 cc. of water, add approximately 0.1 N iodine till the liquid has a faint yellow color. Make t o a volume of 100 cc., and mix thoroughly. T o 5 cc. of the solution add 5 cc. of water, 1 cc. of 0.1 N hydrochloric acid, and I cc. of a 10 per cent solution of barium chloride. Any turbidity should not be greater than is produced by 0.05 mg. of SOr under the same conditions. Specifications PreviAusly Published
(1) Committee on Analytical Reagents, IND.END. CHEM.,17, 756 (1925). (2) Ibid., 18, 636,759 (1926). (3) Ibid., 19, 645 (1927). (4) Ibid., i9, 1369 (1927). (5) Ibid., 20, 979 (1928). (6) Ibid., Anal. Ed., 1, 171 (1929). (7) Ibid., 2, 351 (1930).
A m m o n i u m P h o s p h a t e (Dibasic) (3) TEST
Heavy Metals-Dissolve 5 grams in 40 cc. of water, add140 cc. of 1 N sulfuric acid, 5 cc. of hydrogen sulfide water, and dilute t o 100 cc. Any brown color which is immediately developed should not be greater than is produced by 0.05 mg. of lead in the same volume of an aqueous solution of a lead salt treated with the same amount of hydrogen sulfide water.
According to a report of the Cmtral Drug Department of the Soviet Government, there are forty pharmaceutical producing plants under the control of the local pharmacy administrations. Last year seventy different state organizations furnished medical stores and supplies, which were distributed to them from a central department. Manufacturers of medicinals in Russia are reported as supplying the greater part of the domestic consumption.
