Mar. , I 9 I 6
T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
The neutral, method detected 8 of t h e 11 poor ones a n d rated I good one as poor. The oat plant showed t h e nitrogen in t h e material from Dr. Brackett t o be of very inferior quality: t h e alkaline method rated 3 as having inferior nitrogen, while t h e neutral method condemned b u t I . TABLEVII-TESTS SOURCE OF
NITROGEN None . . . . . . . . . . . . . . . . . . . . . . . . .
OF 1914 FERTILIZERS, ETC. AvailWeight of Activity by ability Permanganate Air-Dry of Oat-Tops Methods Alk. Neut. GriLms N 0 .. .. 12.5 10 48 43 76 56 32 29 87 70 21 12 73 50 49 63 51.5 89 63 55 59.5 86 77 70 69 86 10 44 17 74 37 55 42.5 89 44 47 55 88 64 59 58 88 41 50 44 74 11 40 20.5 74 51 65 54 88 28 34 65 50 61 68 59.5 89 48 15 77 22.5 63 68 64 64.5 59 44 78 48.5 1 35 60 13 26 57 86 35 6 49 16 80 0 23 10.5 85 56 52 .. .. 104 91.5 .. , . 80 76.5 .. ..
74 84
80 93
.. ,.
..
82 65.5 158 105
91 68 191 118
.. , . .. ..
..
,.
.. .. ..
S U h l MARY
I-Rye and oat plants grown during late fall and early winter conditions did not make as large a growth as those grown after midwinter for t h e same period under otherwise t h e same conditions, b u t t h e amount of nitrogen removed in t h e tops of t h e plants was much the same in both experiments. 2-Although t h e rye plants did not make as large a growth as t h e o a t * p l a n t s , t h e relative growth was much t h e same with those having like treatment. 3-Plants having their nitrogen added in t h e form of garbage tankage or aluminum nitride made no larger growth t h a n those t o which no nitrogen was added. 4-Nitrogen in water-extracted blood proved just as available t o t h e oat plant as t h a t in t h e unwashed blood. j-Plants securing their water-insoluble nitrogen in animal tankage made fully as large a growth as those receiving it in blood. 6-The water-insoluble nitrogen in castor pomace and rape meal proved excellent sources of nitrogen for t h e growth of oat plants while Kanona tankage proved t o be quite a n inferior source of nitrogen. 7-An application of 0.6 g. nitrogen in Cyanamid (16; Ibs. of nitrogen per acre) proved toxic t o t h e young plants b u t they were able t o overcome t h e toxicity and make a fair growth. 8-All the water-insoluble nitrogen in t h e material received from Dr. Brackett, A. 0. A . C. referee on nitrogen, proved t o be of inferior value when subjected t o t h e plant test. 9-The nitrogen in soot had a n availability of 56 compared with t h a t in blood at 80.
251
Io-Nitrogen in oxamide produced plant growth about equal t o t h e average produced by t h a t in blood and in nitrate of soda. I I-Lower activities, secured by modifications of the neutral permanganate method, in general agree no better with t h e availabilities t h a n those secured by t h e unmodified method. 12-Of t h e 56 fertilizers tested, not only by the oat plant but also b y t h e alkaline a n d neutral permanganate methods, 24 were found t o contain waterinsoluble nitrogen having a n availability of less t h a n 4 j as compared with blood nitrogen a t 80; of these, 13 were actually classed as inferior by having an activity of less t h a n j j by t h e alkaline permanganate method, and 3 more were practically so classed, their activities being only one t o two points higher: 2 having availabilities of only j 4 and 50 were condemned None was condemned by by activities of j~ and 41. t h e alkaline method which proved t o have a high availability. 13-The neutral method', on t h e basis of activities of less t h a n 8 0 , detected 19 of t h e 24 inferior ones a n d three more having availabilities of only 54, j o and 49, b u t unfortunately condemned three with t h e satisfactory availabilities of 81, 74 a n d 68. 14-Concerning the A. 0. A. C. inferior nitrogenous material, distributed for cooperative work in 1914, t h e inferiority of 3 of t h e 4 samples was detected by the alkaline method, whereas only I of them was detected b y t h e neutral method. I j-It will be seen t h a t about t h e same percentage of t h e inferior samples was detected b y t h e t w o methods, b u t t h a t t h e neutral method condemned some samples which proved t o have satisfactory availabilities according t o t h e vegetation tests. 16-The percentage of t h e insoluble nitrogen a t tacked by t h e potassium permanganate solution agrees much closer with t h e relative availability by vegetation test, in case of t h e alkaline t h a n of t h e neutral method. AGRICULTURAL EXPERIMENT STATION RHODEISLAND STAT% COLLEGE KINGSTON, R. I
A PROPOSED NEW METHOD FOR CITRATE-INSOLUBLE PHOSPHORIC ACID B y CHAS. H HUNT Received September 24, 1915
There is, perhaps, no other point in t h e chemistry of fertilizers which has called forth so much discussion and difference of opinion as t h e method for t h e determination of citrate-soluble or reverted phosphoric acid by means of neutral ammonium citrate. The present arbitrary method for this determination is unsatisfactory and also unscientific, since t h e same substance frequently gives different results in the hands of different analysts. If a method could be found t h a t would measure the amount of citrate-insoluble PzOj and, indirectly, t h e amount oE citrate-soluble PzOj, in which there are not so many factors t h a t influence t h e results, i t would be of great aid to t h e fertilizer chemist. It is believed t h a t t h e method proposed below will, in a way, help solve t h e problem.
25 2
T H E J O U R N A L OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
It has been known for some time t h a t lime,l limestone and other forms of calcium2 added as a filler or as a n essential ingredient in fertilizers, decreases t h e available Pzos, or, in other words, increases t h e citrateinsoluble PzOE,and also, t h a t thc rate of increase in the amount of citrate-insoluble PzOs is proportional t o t h e amount of added calcium. This fact has been further confirmed in this laboratory. I t is believed t h a t t h e explanation for this is t h a t t h e calcium, in whatever form it may be, reacts with t h e mono- and dicalcium phosphate, in the ammonium citrate medium, a n d changes them into the tricalcium phosphate, a form which is supposed t o be insoluble in neutral ammonium citrate, according to t h e following equations : 2H20 CaH4(POq)2 zCaO = C a 3 ( P 0 4 ) 2 CazHZ(P04)z CaO = Caa(POr).? H2O Whether a similar reaction takes place in those fertilizers containing no added lime or other forms of calcium t h e writer is not able t o say iust now, b u t i t has been noticed t h a t there is a fairly constant ratio between the amount of calcium oxide, determined asrsuch, both in those fertilizers t h a t do and those t h a t do not contain added calcium compounds, and the citrate-insoluble Pz05,as is shown in Table I . The proposed method is based upon some of these facts.
+ +
+ +
Per cent calcium oxide 20.00 11.72 11.50 31.80 4.06 27.34 13.78 19.35
~
Wash. Agric. Exp. Station, Bull. 116. THISJOURNAL,6 (1914), 20; also 6 (1913). 933. 3 U. S. Dept. Bull. 107, Rev. Ed., P. 2. . AEric.. 4 Perkin, ‘‘Qualitative Chemical Analyses.” p. 86, foot-note. If iron is present it will be precipitated here. 5 U. S. Dept. Agric., Bull. 107, Rev. Ed., p. 4. 2
~~
Ratio of citrate. Per cent(a) insoluble PnOs Per cent P2Os citratet o PnOr precipitated insoluble precipitated FERTILIZER with ammonia PaOj with ammonia M e a t and bone.. . . . . . . . . . . . . . . . 22.45 1 : 1.29 17.39 Concentrated fertilizer. . . . . . . . . . . 19.75 1 : 1.82 10,80 1 : 1.46 Vegetable ..................... 19.00 13.02 Meat and b o n e . , . . . . . . . . . . . . . . . 15.35 1 : 1.68 9.10 Rose l a w n . . . . . . . . . . . . . . . . . . . . . 20.90 1 : 1.68 12.60 Lawn fertilizer.. . . . . . . . . . . . . . . . 14.15 1 : 1.67 9.43 Concentrated. . . . . . . . . . . . . . . . . . 13.60 1 : 1.52 9.06 Bone meal. .................... 22.35 1 : 1.39 16.03 Bone m e a l . . . . . . . . . . . . . . . . . . . . . 19.70 1 : 1.40 14.07 Blood and b o n e . , , , , , , , , , . , . , , , 14.90 1 : 1.48 10.04 Fish fertilizer. . , , , , , , , . , , . , , , , 8.85 1 : 1.37 6.47 ( a ) Determined by Official me:thod.
.
It is seen t h a t t h e ratio between t h e citrate-insoluble PzO5 and t h a t precipitated with ammonia is about I : 1.50. Hence, by dividing t h e amount precipitated with ammonia by r . j o we obtain a figure which is approximately equal t o t h e citrate-insoluble P206 as obtained by the Official method. This ratio varies in some cases. The proposed method does not seem applicable t o superphosphates, perhaps due TABLEI11
Per cent Fertilizer Bone m e a l . , . . . . . . Bone m e a l . , . , , . . Bone m e a l . , ...... Bone meal.. . . . . . . Bone meal.. , , . , . . Bone meal.. ......, . . Bone m e a l . . ...... . . . Bone m e a l . . . . . . . Bone m e a l . . . . . . . . . . . Bone m e a l . . ... Bone meal.. ...... Bone meal.. ...... Bone meal.. . . . . . . Bone m e a l . , . . . . . . Tankage. . . . . . . . . , . . Tankage. . . . . . . . . Tankage. . . . . . . . . . . . Tankage. . . . . . . . .. . . ... Tankage.,. . . . Tankage.. . . . . ... Tankage, . . . . . Tankage Tankage. . , , , . , . . ... Tankage. , , , , . . , . . . . Tankage, . . . . . . . . . . . Bone and blood.. . . . . Meat and bone.. .. Meat and bone.. .. . . . Meat and bone. ... . . . Fish g u a n o . , . . . . . . . . Fish guano.. . . . . . . . . Fish g u a n o . . . . . . . . . . Sheep guano.. . . . . . . . Sheep guano.. . . . . . . Complete fertilizer Complete fertilizer Complete fertilizer Complete fertilizer Complete fertilizer Complete fertilizer . . . Complete fertilizer . . . Complete fertilizer ... Complete fertilizer . . . Complete fertilizer . . . Complete fertilizer Complete fertilizer Complete fertilizer Complete fertilizer Complete fertilizer Complete fertilizer
No.
.
(
I
.
...... ...
...
YETR OD
1
This
TABLB - I1
Ratio citrateinsoluble PaOs t o calcium oxide 1 : 2.34 1 :2.41 1 :2.38 1 : 1.91 1 :2.25 1 : 2.53 1 : 2.20 1 : 2.29
The fertilizer is digested as in t h e Official method3 for total phosphoric acid and made up t o a definite volume. ,4n aliquot is then taken a n d a n excess of ammonia is added whereupon a white precipitate of tricalcium phosphate is f ~ r m e d . ~It is then filtered a n d washed thoroughly m-ith water. The precipitate is dissolved on t h e filter paper with nitric acid and t h e phosphoric acid determined in t h e filtrate according t o t h e volumetric optional method.’ From this investigation i t has been found t h a t t h e phosphoric acid is in excess of the calcium t h a t is necessary t o combine with i t t o form tricalcium phosphate, or t h a t all of t h e phosphoric acid is not precipitated with ammonia. N o w t h e amount of tricalcium phosphate precipitated with ammonia depends upon the amount of calcium present in t h e Eertilizer. Also t h e amount of citrate-insoluble P205 depends upon t h e amount of calcium as has already been pointed out. if the amount of calcium governs these two factors then there must be some
a, so.
definite ratio between the factors themselves. ratio is shown in Table 11.
TABLEI Per cent citrateinsoluble FERTILIZER PzOa Tankage.. . . . . . . . . . . . . . . . . . . 8.55 Tankage . . . . . . . . . . . . . . . . . . . . . 4.85 4.83 Tankage . . . . . . . . . . . . . . . . . . . . . . Bone meal . . . . . . . . . . . . . . . . . . . . . 16.65 Fish fertilizer.. . . . . . . . . . . . . . . . . 1 . 8 0 Complete(a), . . . . . . . . . . . . . . 10.80 Complete(a). . . . . . . . . . . . . . . . . . . 6.25 Complete(a) . . . . . . . . . . . . . . . . . . . 8.45 (a) Contains added calcium compounds.
voi.
.
.
I
iV
2.98 3.02 0.94 3.73 4.08 3.94 3.98 4.06 3.66 4.07 2.63 4.31 3.85 4.08 4.37 7.23 7.07 7.05 5.58 5.27 7.13 8.47 4.72 7.93 3.38 4.05 6.48 2.64 7.18 13.60 7.11 9.34 3.77 4.48 2.95 2.70 2.44 3.90 5.61 3.02 4.45 3.99 3.19 1.98 2.05 3.08 4.60 i.17 3.32 3 48
Per Per cent Per Per cent cifrate- cent cent water- inPzOj total soluble soluble €Jew P20~ PzOs P2Os method
Diff. -2.43 -2.71 -5.87 -2.80 -1.13 -0.94 -4.38 t1.86 -1 49 -2. 15. ‘1.75
-0.90 +0.85 --1,77 +2.08
+1.78 t0.80 +0.34 12.84 -0.10 +1.56 -0,26 +1.26 +1.86 +0.82
-0.11 +1.13 -0
. . 7. .7
+0.21 -0.40 -0.57 -1.37 +0.20
+0.01
-1,65 +2.36 -0.36 +1.51 1-1.33 i0.35
f0.98 +O.ll -0.17 +1.35 L2.23 t2.35 t0.87 +0.50 -1.65 11.12
has been t o t h e fact that a large part of the removed as water-soluble P205. Also, since t h e amount of citrate-insoluble P205 in a fertilizer depends upon t h e amount of material digested,’ we can readily account for t h e low results in t h e case of those fertilizers containing a large amount of water-soluble P z O ~ , because t h e amountof material treated has been con1
Wiley, “Principles and Practice of Agricultural Anal.,” Vol. 11, p. 136.
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
Mar., 1916
siderably decreased from t h e amount supposed t o be used in making t h e determination. If t h e amount of citrate-insoluble Pz05depends upon t h e weight of material digested, .is it not illogical t o determine t h e amount of citrate-insoluble Pz04on a 2 gram sample in t h e case of bone meal or tankage a n d make t h e same determination on t h e residue of a 2 gram sample, after t h e water-soluble PzOs has been removed, which, in many cases is much less t h a n z grams, in t h e analysis of a mixed fertilizer containing superphosphate? Results obtained, on t h e same sample, by the Official method and t h e proposed new method are given in Table 111. While these results vary somewhat, there is yet a degree of uniformity in t h e variations. Those obtained by precipitation with ammonia are usually lower t h a n those by t h e Official method in t h e case of bone meal a n d generally higher in t h e case of tankage a n d complete fertilizers. The plus and minus errors for all classes of fertilizers reported are nearly equal t o each other, which fact seems t o suggest a possibility of using a different factor for different types of fertilizers. Again, it is noticeable t h a t t h e differences between those obtained by t h e Official a n d proposed methods are, in most cases, no greater than t h e variations in those obtained by different analysts working upon t h e same sample, when t h e Official method is used.
253
LABORATORY NOTES ON THE STANDARDIZATIQN OF THE MERCURIALS By DONALD K STRICKLAND
Received September 7 , 1915
Six methods for t h e estimation of mercury were submitted for study,I by the committee on quantitative methods of the division of pharmaceutical chemistry of t h e American Chemical Society. These included: ( I ) t h e Hempel volumetric method for mercurous chloride, bromide and iodide, involving t h e use of iodine a n d sodium thiosulfate solutions; ( 2 ) a modification of t h e method of Rupp, in which t h e metallic precipitate is redissolved in nitric acid and reprecipitate as mercuric iodate, which at length is determined volumetrically by the use of sodium thiosulfate; (3) a n electrolytic method;2 (4) the well-known Rupp3 formaldehyde method for mercuric salts; (5) a method in which mercuric arsenate is weighed; and (6) a gravimetric estimation as mercurous chloride. These methods were studied with t h e object of devising methods which might be used as pharmacopoeial methods, where a standard of purity for mercury salts has been required, without offering an official method of examination The methods in use to-day for establishing t h e standard of purity of these chemicals are no doubt quite uniform a n d t h e best methods have long since been S U M M A R Y A N D COKCLUSIONS established in practice. These were pointed out by I-Lime, limestone and other calcium compounds, C. E. Smith.4 The Hempel method serves best for added as a filler or as a n essential ingredient increases t h e analysis of calomel a n d mercurous iodide, while the citrate-insoluble PzOS. mercuric chloride, iodide, and ammoniated mercury 11-The ratio between the calcium oxide, determined are analyzed by the method of Rupp. For oxide of as such, and t h e citrate-insoluble PlOs is fairly con- mercury t h e method most serviceable is t h a t of R . s t a n t both in those t h a t do a n d those t h a t do not con- Cohn5 simplified by R u p p a n d Kraus,O which is found tain added calcium compounds. in t h e German Pharmacopoeia. 111-In t h e proposed method t h e fertilizer is diRecently t h e effort has been made, not only t o gested as for total Pz05. An aliquot is made alkaline determine t h e purity of these salts as they enter into with ammonia a n d t h e P206 is determined in t h e t h e manufacturing processes, b u t also t o standardize precipitate thus formed. t h e finished products, especially in tablets and pills. IV-The ratio between t h e citrate-insoluble PzOs L. F. Kebler’ reported the results obtained upon and t h e Pp06 precipitated with ammonia is about analysis of 30 samples of catomel a n d of calomel and I : 1.50. sodium bicarbonate tablets, 1 2 of which (or 40 per V-By dividing t h e amount of PZOSprecipitated cent) varied more t h a n I O per cent from t h e claim with ammonia by 1.50 we obtain a figure which is on t h e label as t o t h e calomel content. I n this they approximately equal t o t h e citrate-insoluble PzOs were slightly more inaccurate t h a n t h e average of t h e determined b y t h e Official method. samples of tablets on t h e American market a t t h a t VI-The plus and minus errors in t h e final results time. I t was found in this investigation t h a t 36.7 nearly balance each other. The fact t h a t t h e errors per cent of all t h e tablets varied more t h a n I O per cent for bone meal are nearly t h e same and t h a t for tankage from t h e standard claimed. At t h e same time, 5 a n d complete fertilizers are also nearly t h e same b u t tablets of corrosive sublimate, out of 17 examined, of opposite quantity, seems t o suggest a possibility were found t o vary IO per cent or more from t h e decof using a different factorfor different types of fertilizers. laration on t h e label. Two antiseptic mercuric VII-The difference between t h e results obtained chloride tablets were examined, both of which were by t h e Official a n d proposed methods are no greater inaccurate by more t h a n IO per cent. I n this imt h a n t h e differences in t h e results obtained b y different portant contribution t o pharmaceutical chemistry analysts working on t h e same sample when t h e Official there are recommended for t h e estimation of calomel method is used. 1 Am. Jour. Pharm, 83 (1911), 186. VIII-The proposed method claims t o be much 2 Smith, “Electro-Analysis,” 90-94. 3 Ber., 39 (1906), 3702. shorter a n d less expensive, doing away with the use 4 A m Jour. Pharm, 83 (1911). 311. and preparation of neutral ammonium citrate. 5 Bey, 34 (1901), 3502. FOOD A N D FERTILIZER LABORATORY, PULLMAN, WASHINGTON
STATE COLLEGE
6
7
Ibzd., 36 (1902), 2015 J . Am. Pharm. Assoc., 3 (1914). 1069.
