T H E JOURiVAL OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
484
11. I n Table VI1 are shown what the fat columns, when corrected for these losses and gains of fat, should read. These results were then compared with those for per cent fat obtained by the Roese-Gottlieb method. Barring some variation due t o the non-uniformity of the charges themselves, the reading of the fat column, according t o calculations, agrees very closely with the results found b y the Roese-Gottlieb method. 111. Further, Table VI11 gives a summary of the losses of fat in the acid-sugar solution and in the bulb solution which losses are the cause for the low per cent of reading of the fat column. The average per cent fat loss is 0.605. On the second set, determinations 5 t o 8, the average is 0.474 per cent. I t is obvious t h a t these losses of fat in the Modified Babcock are almost twice as great as in cream testing. Thus multiplying the average f a t loss 0.28 per cent, in cream, as found by Hunziker, b y 2 and comparing this with twice the amount of fat drained off, 0.256 per cent, gives approximately the same fat loss as found in the Proposed Modified Babcock test. SUMMARY
The above facts warrant the following conclusions: I . That the same factors obtain a s in cream testing with one exception, t h a t of draining off the acid-sugar solution involving a fat loss of 0.258 per cent.' 2 . The loss of volatile fatty acids is insignificant, having no effect on the accuracy of the fat reading. The same is true of glycerol. 3. The per cent impurities in the fat column in this proposed test is higher than in cream testing because the conditions under which the end point is worked out are somewhat different. The darker color of the fat column itself also substantiates this. 4. Uncompensated losses of f a t are caused by the fat lost in the first drain, the acid-sugar solution, and in the bulb solution. This loss is approximately twice as great as in cream testing. MISSOURI DEPARTMENT O F FOODAND DRUGINSPECTION
COLUMBIA
TINCTURE OF IODINEa B y L. F. KEELER
This coinmodity has probably been examined inorc frequently than any other simple drug offered for salc by the retail trade, and I know of no medicinal agent which has more frequently been found wanting. Observations and investigations have frequently shown t h a t when iodine was dissolved in simple ethyl alcohol there was a great tendency for the iodine t o be changed into hydriodic acid and other compounds thus actually lowering the free iodine content and the diminution increased with the age of the preparation. Experiments conducted t o obviate this difficulty indicated that the presence of potassium iodide tended t o inhibit the usual combination of the iodine and thus increase the stability of the tincture. The method outlined for the manufacture of this commodity b y the last (8th) revision of the U. S. Pharmacopoeia preTHISJOURNAL, 6, 403. Read before the City of Washington Branch American Pharmaceutical Association, February 12, 1913.
Vol. 5, No. 6
scribes the use of a certain amount of potassium iodide. The shortcomings of the tinctures available on the market have, however. not been materially reduced. Almost every state board which has taken up this question has found that a large number of the samples are deficient in iodine content. This shortcoming cannot now be so fully ascribed t o deterioration, neither can i t be ascribed t o difficulties in manufacture because the process of manufacture is extremely simple. During the past few years a considerable number of samples of tinctures of iodine have been examined in the Bureau of Chemistry. The samples shipped into interstate commerce were found t o comply closely with the pharmacopoeial requirements. All of them contain the requisite amount of potassium iodide. A goodly number of samples were collected in the District of Columbia and analyzed with the following results: ANALYSISOF TINCTURE OF IODINE POTASSIUM IODIDE ALCOHOL Per Per I Grams cent .variGrams cent vari- Per cent volume DECLARATION per 100 cc. ation(a) per 100 cc. ation(a) 74 Correct. 71.5 1.3 86 1.97 Not declared. 100 None 93.5 3.42 50 #, " 7.5 85 5.38 36 4.40 94.4 100 27 None. 5.04 40 Small type. 95 3.03 5 .08 26 Correct. 100 Trace 91 26 5.09 58 95 22 2.1 5.36 Not declared. 6 5.30 95 5.52 19.5 93.5 5 .84 17 19.5 5.57 Currcct. '93.5 None 5.03 5.SI 15 Not declared. 95 None 100 14.5 5,SS 92 R 100 14.5 Kone 5.89 C orrec't . 36 V4.5 6.82 12.5 6.06 Not decldrcd. 80 93.5 1.02 11 6.09 Correct. 95 1 4.93 6.11 10 91 7 5.37 6.18 10 11 4.45 93 6.18 10 88 13.5 4.32 6.24 9 Not declared. 46 2.79 91 8 6.29 Small type. 8 4.61 91 8 6.29 Not declared. 2.58 91 48.5 S 6.32 Small type. 93.6 None 100 6.34 7.5 Not declared. 23 93.5 7.5 3.84 6.36 Correct . 2 95 4.92 6.48 5.5 88.5 24 3.81 6.48 5.5 7 Small type. 95 5.34 6.49 5.5 Correct. 95 30 6.52 6.73 0.5 51.5 96 2.42 6.75 0.5 s5.5 24 Small type. 3.82 0.5 6.76 90.5 51 Correct. 2.46 ... 6.78 Not declarrd. 21 91 3.95 6.80 ... " I' 86.530 3.49 6.80 ... 11 Incorrect. 93 5.56 6.84 ... Correct. 2 92.72 6.85 5.1 ... 95 Small type. 50.5 0.97 ... 6.90 ' I ' I 91.5 100 None 0.5 6.97 Not declared. 16 91 5.79 2 .o 7.00 Small type. 91 10 5.52 2.5 7.03 Correct. 93.5 None 5 .oo 2.5 7.04 89.5 8.5 4.58 4.5 7.18 90.5 3 4.5 5.17 7.21 Nut declared. 88.50 13.5 5.67 4.5 7.21 I' '' 3 90 5.14 5.5 7.24 2 94.5 Correct. 10.5 5.12 7.58 Not declsrpd. 86 10 15.6 4.50 7.95 90 Small type 12.5 4.38 17.5 8.07 91.50 Not declarrd. 23 3.86 18 8.11 Correct. 20 95 18 6.00 8.11 Not declared 9 89 5.45 21.9 8.37 I, 8' 4.5 89.5 5.23 9.26 35 IODINE
-
--
1
2
(a)N. B.-Thc per cent variation in the above analyses is calculated to the nearest half per cent,
The pharmacopoeial tincture contains about 6.56 grams of free iodine and j grams of potassium iodide in I O O cc. The range of variation (1.97t o 9.26 grams per I O O cc.) is certainly remarkable. What real valid excuse can be offered for either of the above extremes? Furthermore, is there any substantial reason for some of the other variations? The permissible variation from the standard must he met sooner or later. Shall i t be stringent or reasonable? If reasonable, shall the variation be j per cent or I O per cent or 2 0 per cent? ('onsidering t h a t the adjective " about" qualifies the ;tmount of free iodine t h a t should be present in the tincture, about 60 per cent exceed a j per cent variation, 40 per cent a I O per cent variation and 18 per c m t a 2 0 per cent variation. I do not believe many manufacturers will contend for or advise a 20 per cent variation in that i t would not only savor of carelessness hut actually encourage it. I s then a I O per cent variation either way from the standard, reasonable, fair and just to the manufacturer, the consumer, the physician, etc., or is i t desirable t o be more stringent? Suggestions are invited either in the columns of TITISJ O U R N A L or otherwise. The free iodine is the cssential factor of this tincture but the potassium iodide and percentage of alcohol must also be considered. The conditions noted above relative t o the variability of the free iodine also hold for potassium iodide. The variation ranges from no potassium iodide to 6.82 grams per r o o cc. Discussion in this connection is also invited. DRUG DIVISION B U R E A UOF CHEMISTRY 1;. s. D E P A R T M E K T AGRICULTURE
THE APPLICATION OF FOLIN'S METHOD FOR THE DETERMINATION O F AMMONIA TO FERTILIZERS B y OTTO FOLIN AND A. W. BOSWORTH
Received March 3, 1913
The determination of ammonia in commercial fertilizers is usually mad.e b y distilling with magnesium oxide.1 I n Folin's method for the determination of ammonia in urine* the ammonia is removed by a strong air current a t room temperature. This method is generally applicable t o all kinds of materials and has the advantage of being both rapid and reliable. I t has been used for the determination of ammonia in meat3 and in cheese.4 The speediness of the determination has been greatly increased by the microchemical modification recently published by Folin and Macu1lum.j By this new method a n ammonia determination can be made in less than half a n hour. This method is applicable to the determination of ammonia in fertilizers. Applied to such products the method is as follows: 'Two grams of fertilizer are placed in a I O O cc. graduated flask, about j o cc. of water added and then 25 cc. of approximately normal hydrochloric Bureau of Chemistry, U. S . Department of Agriculture, Bull. 107 (revised). a Folin, Z . Dhvriol. Chem., 37, 161. Pennington and Greenber, J . A m . Chem. Soc., 32 561. 1 Bosworth nnd Winter. Rureau uf Chemistry, TJ. S . Ilepnrtment o f Agriculture, Bull. 152. 6 Folin and Maculluni, J . B i d Chum., 11, ,523.
acid. The volume is now made up to I O O cc. with water, the contents of the flask are shaken, and after standing a few minutes are shaken a second time. The flask is now allowed to stand until the heaviest of the undissolved particles have settled. Five cc. of the supernatant liquid are withdrawn by means of :L pipette (filtering is not necessary) and transferred to the tube of the Folin apparatus. Two cc. of a saturated solution of potassium oxalate, a few drops of kerosene and finally z cc. of a saturated solution of potassium carbonate are added. The apparatus is immediately closed and air passed through for I O to 20 minutes. The ammonia is collected in a flask or test tube which contains z o cc. of seventieth normal hydrochloric acid. If the air current is produced by a blast the ammonia is collected in a flask and 2 j cc. of water are added to the 2 0 cc. of acid in order to increase the volume and thus prevent the loss of ammonia. After the distillation, the contents of the flask, or test tube, are titrated back with seventieth normal sodium hydroxide, using alizarin red as indicator. The percentage of nitrogen as ammonia is found by subtracting the number of cubic centimeters of alkali used from the number of cubic centimeters of standard acid used, and dividing the difference by five. Diagrams of the apparatus with descriptions have been given b y Folin and Farmer.1 The method as given has been tried on several samples of fertilizers and the results obtained, together with those obtained by the magnesium oxide method, are given in the table below. The two sets of results were obtained b y different persons, working in different laboratories and the results by the Folin method were obtained several months after those by the magnesium oxide method. The samples are representative of what may be found on the market. NHsby NHaby Sample the Folin distilling Total number method with MgO nitrogen 1 2 3 4 5 6 7 8 9 10 I1 12 13 I4 15
16 17 18 19 20 21 22
0.00 0.08 0.11 0.03 0.03 0.08 0.20 0 06 0.22 0.15 0.29 0.31 0.43 0.70 0.69 0.90 1.04 1.37 1.47
0.00 0.05 0.06 0.08 0.13 0.13 0.17 0.17 0.20 0.20 0.38 0.39 0.42 0.65 0.77 0.89 1.07 1.35 1.44
1.43
1.59
2.31 2.72
2.33 2.58
2.10 3.20 8.24 5.11 1.51 5.25 2.07 1.13 3.43 3.09 3.13 2.46 1.09 4.71 2.83 2.29 2.16 2.58 3.99 4.02 4.07 3.08
Chief source of nitrogen nitmte, organic
organic nitrate, orgnnic organic nitrate, organic
organic, ammonia nitrate, organic. ammonia I' ammonia organic ' I nitrate, organic. nnimr)iiin organic, ammonia '' nitrate " urgiinic, xmniABORATORY
IIARVARD MEDICAL SCIIOIX
Rosro?i 1
I'olin and Farmer, J. Biol. Chem., 11, 493.
