May, 1919
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in Palestine phosphates Charles2 found fluorine in 88 out of 93 samples of mineral and sea waters tested, t h e amount of sodium fluoride lying between 0.005 and 0.012 g. per 1. River waters examined b y Gautier and Clausman3 were found t o contain 0 . 0 2 t o 0.6 p. p. m. Hillebrand4 found 5.2 p. p. m. fluorine in t h e water from Ojo Caliente, near Taos, N. M., and Gautier5 found t h e spring a t Vichy t o contain 0.43 5 mg. and t h e one a t Luxiel 0.296 mg. fluorine per liter. Carnote found 0 . 8 2 2 g. fluorine per cu. m. of ocean water. The occurrence of fluorine in spring and stream water is a strong indication of the presence of fluorine in the soils of t h e region from which they draw their supply of water. TABLEI
be dissolved t o give a solution of which a I cm. layer would reduce exactly Io-fold t h e intensity of a beam of light of t h e wave length in question. I n Figs. 2, 3 and 4 t h e absorption spectra of t h e dyes prepared in this laboratory are shown by the full or broken lines, those of t h e German and British preparations studied b y crosses and circles, respectively. COLOR LABORATORBURZDAU OB CHEMISTRY WASHINGTON, D. C.
RELATION OF FLUORINE IN SOILS,PLANTS, AND ANIMALS‘ By I,. A. STEINKOENIO Received November 4, 1918
Fluorine is so generally distributed in t h e mineral, vegetable, and animal kingdoms t h a t one must expect t o find i t in soils, the source of supply of inorganic constituents of plants and indirectly of animals. Among t h e fluorine-bearing minerals found in soils examined mineralogically by McCaughey and Fry2 are t h e following: biotite, found in 2 1 soils out of 2 5 examined, tourmaline in 21, muscovite in 20, apatite in 12, fluorite in 4, and phlogophite in I. I n 8 soils biotite was found t o be abundant, in one soil tourmaline, and in 6 soils muscovite. The amount of fluorine carried by these minerals3 varies as follows: biotite, trace t o 4.23 per cent; tourmaline, 0.06 t o 1.19 per cent; muscovite, 0 . 1 2 t o I . 2 6 per cent; apatite, 1.31 t o 3.86 per cent; fluorite, 48. g per cent; phlogopite, 0.82 t o 5 . 6 7 per cent. Fluorine is a common constituent of igneous rocks.4 Gautier5 found it t o be an almost universal constituent of volcanic rocks, and Danellie found i t in amounts of 3.5 t o 4.88 per cent 1
2
*
Published with the permission of the Secretary of Agriculture. U. S Dept. Agr., Bureau of Soils, Bull. 91 (1913). Dana, “A System of Mineralogy,” Pub. by John Wiley & Sons, Inc.,
1914. 4 Clarke, “Data of Geochemistry,” U. S. Dept. of Int., Geol. Survey, Bull. 616 (1916). 8 Compt. rend., 167, 820. 0 Rend. sac. chem. ital., [Z] 4. 165.
Fluorine in 100 g. Fresh Substances PLANT Mg. Grains: Corn meal.. , , 0.83 Corn bran 0.59 Corn meal.. . . 1.17 0.36 Corn bran.. Coru meal. , , , , 0.7 1 0.52 Rye meal.. Barley meal.. . . 0.20 Rice...................................... 0.80 Legumes: Kidney beans.. , , , 1.70 Lentil.. .. , 1.56 Kidney beans (green). , 0.019 Lucern 1.30 Crucifers: Cabbage (head) 0.088 Cauliflower.. , . , , 0.21 French turnip (root). 0.14 Radish root,. , , 0.06 Cress 0.24 Long r a d i s h . . . . . . . . . . . 1.45 Mustard seed.. 0.76 Mustard leaves 0.01 Fruits: Pear pulp 0.022 Apple pulp., 0.034 Apple skin.. . . 0.76 Peach m e a t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.29 Peach s t o n e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.74 A ricotmeat 0.30 Cterry meat and skin.. 0.37 Strawberry.. 0.12 Miscellaneous: Potatoes 0.084 Tomatoes... ......... 0.20 Buckwheat.... 2.17 Sorrel.. , . , 13.87 Carrots (root). . .. . . . . . 0.036 Asparagus (young shoot). , , ,, , 0.52 Spinach.. . . 0.37 Beet............... 1.00 Walnut 0.68 Hay 0.40 Straw of grains.. , , ., , . ,. , , 0.94 0.34 Poplar wood). . , . . , . . , Poplar !bark). . . . . . . . . . . , . . . . . . 0.34 Fir (wood) 1.30 Pine 1.45 , , .. 0.59 Oak wood) Oak tbark) 0.48 1.04 Birch (wood) Birch (h Walnut
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....... ...... .. .. .. .... .. .. .. ... .. ...... .. . .... .... ..................................... . .. . .. . . .................... . . . . . . . . . . .. . .. .. ... ............................ ................................. ...... .. .. .. .... .. .... .... .. .... .. .... .. .... .. .... ... .. .. .. .............................. . . . . . .. . . ........ .. .. .. .. .. .. .. .. .... .... .... ...... .................................. ..................... . ... .............................. ....... ... . .. . . . .. .... ... ...... .... .. .. .. .. .... ... . . . . . . . . . ............ . .. .. ... . ... . .. ...... ....................... ................................... ...................................... . . . . . . . . . . . . . .. .. .. . .. . . . .. . .. . .. . .. .. . .. .. ...... ................................ ...................................... ............. . .. . . ... .. . .... ................................ ..............................
Woodman and Talbot’ found fluorine in all of a large number of samples of barley, malt, brewing sugars, ales, and beers with a standard content of I O mg. per liter. Kickton and Behncke,* in go per cent of t h e wines they examined, found fluorine in amounts too small t o be considered fluorine added as a preservative. An average of 2 . 6 5 mg. of fluorine in IOO 1 Soils are largely made up of more or less disintegrated rock, and the minerals named above furnish a source of supply of inorganic compounds to the plants growing on the soils. 2 Compt. rend., 144 (1907), 37, 201. 8 Ibid., 168, 1389. 4 U.S. Geological Survey, Bull. 118 (1893), 114. 6 Compt. rend., l S T , 820. 6 Ann. Mines, 191 10 (l896), 175. 7 J. Am. Chem. Soc., 29, 1362. 8 Chem. Abs., 4 (1910). 3118.
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g. of dried material was found by Gautier and Clausman1 in the examination of 63 food plants. I t was found more abundant in t h e leaves and in t h e skins of the fruit than in t h e pulp. A high phosphorus content usually went with a high fluorine content although t h e fluorine t o phosphorus ratio was found more variable in plant t h a n in animal tissue.2 Gautiefj found fluorine to be beneficial t o the growth of plants in artificial media in the majority of cases and in some cases t o be of doubtful value. The content of fluorine found by Gautier and Clausman in some plants examined are given in Table I. Seldom does t h e percentage of fluorine rise above 0.002 per cent and most times is under 0.001 per cent. This would place it among the rarer elements in plants and its concentration runs more nearly parallel t o rubidium4 than any other element. P. Charles5 found 2 t o 4 mg. fluorine per IOO g. dried material of land mollusks and concluded t h a t fluorine is present in all mollusks and t h a t it is a n “agent of formation and consolidation of t h e skeletons of all animals.” Fluorine was found in the leaves6 of the plants on which the mollusks feed and t h e land mollusks were found t o contain a considerably smaller amount of the element t h a n t h e marine variety. G. Sontag7 determined t h a t the normal content of teeth and bones of a dog is not over 0 . 3 per cent, but by feeding sodium fluoride t o t h e animal it could be raised t o 1.73 per cent in dried fat-free bones and 1 . 2 9 per cent in dried teeth. Gautier* divides the organs of t h e animal body into three classes: I-Tissues of highest vitality, such as nerve tissue, glands, muscles, lungs, etc. (with approximately I t o 4 mg. fluorine per I O O g. dried matter) with fluorine t o phosphorus ratio of I t o 450. 2-Tissues of medium vitality such as bones, tendons, cartilage, etc. (with an average of 4 2 mg. fluorine per IOO g. dry substance), with a fluorine t o phosphorus ratio of I t o 125. 3-Tissues of lowest vitality and destined t o be eliminated (with an average of 14 mg. fluorine per IOO g. dry substance) with a fluorine t o phosphorus ratio of approximately I t o 6. Gautierg regards fluorine as the agent which fixes phosphorus in the cell t o form an organic nitrogenous compound, one part serving t o unite with 3 50 t o 7 5 0 parts of phosphorus in the most vital tissues. Edarek’o found from 2 . 2 t o 2 3 g. fluorine per kilogram of dried tissue in different organs of two accidentally killed men. The constant occurrence of fluorine in the living tissue of both animal and plant and its association with phosphorus is a strong indication t h a t it plays an import a n t r81e in the life of t h e cell. I n the soils examined, fluorine was determined by Compt. rend., 162 (1916), 105. Ibid., 162 (1916), 105. 3 Ibid., 160 (1915), 194 4 U. S Dept. Agr., Bull. 600 (1917), 9. 6 J . pharm. chim., [61 26, 101. 6 P Charles, Compl. rend., 144, 1240. 7 Chem. Zentr., 1 (1916), 1095. 8 Compf. rend., 76 (1914), 170 9 Ibdd., 168, 159. 10 2 physiol. Chem , 69, 127. 1 2
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Merwin’s method‘ with slight modification. The method followed is here briefly outlined: Two grams of soil are mixed with 6 g. of sodium and potassium carbonate mixture and fused carefully over the Bunsen flame. The melt is disintegrated in 250 cc. of water and manganates are reduced by a drop of alcohol. 3 g. of ammonia carbonate in solution are added to the mixture. The solution is filtered through a washed filter paper and slowly evaporated with I g. of ammonium carbonate to a volume of 50 cc. and filtered into a IOO cc. measuring flask. 3 cc. of 3 per cent hydrogen peroxide are added and the solution brought to slight acidity (indicated by orange color) with I : 3 sulfuric acid. 3 cc. of concentrated sulfuric acid are then added and the solution brought t o room temperature by a short immersion in ice water. After bringing to volume and mixing, the solution is compared with one containing 0.01g. oxidized titanium oxide (Tion)in the same volume and of the same acidity. With the standard at IOO divisions on the tube of the colorimeter, the reading of the blank (due to bleaching action by sodium sulfate) should not be much over 120. If it is, sodium and potassium carbonate containing less fluorine should be used. The difference between the test reading (with standard solution at IOO divisions) and the reading of the blank, divided by 23,000 gives the grams of fluqrine in z g. of sample. Duplicates on soils containing the lower amounts of fluorine, usually agreed within 0.01 per cent and those containing the higher amounts within 0.05 per cent. The average values were taken. Merwin’s method is recommended by earlier authorsa2 Difficulty was experienced on account of the presence of chromium in one of t h e samples (Cecil clay subsoil, Charlotte, N. C., CrzOa = 0 . 0 2 5 per cent). The yellow color of the chromate produced during fusion persisted and interfered with t h e colorimetric determination.3 I n t h e remaining samples there was no trouble from this source. The method is not delicate enough t o indicate with certainty the presence of 0.01 per cent fluorine, so as much as this may be present in places where it was reported as n o t found or as a trace. Results of the determination are given in the following table:4 TABLEI1
Depth Inches SOILAND LOCATION Norfolk sandy loam, 3l/z mi. east of Laurinburg, N. C. 0- 8 8-36 Hagerstown loam, Conshohocken, P a . , , , . . , 0- 8 8-24 Gloucester stony loam, Marlboro, N. H.. . . , . . , . . . . , 0- 8 8-36 Cecillsandy loam, Charlotte, N. C.. . . . , . . . . . 0- 8 8-36 Cecil clay, Charlotte, N. C.. , , , , ,. . . 0- 6 6-36 0-10 Durham sandy loam, Archer, N. C.. . . ,. . . 10-36 0-10 Yorkzsilt loam, Bethany, S. C.. . . . . . . . . . . . . . . 10-22 Louisa loam, 1 mi. northeast of Trevilians, Va.. ,., . 0-10 10-36 Pennzsilt loam, Norristown, Pa.. , , . , ... . 0 9-24 - 9
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1
Fluorine Per cent 0.01 0.01 0.11 0.15 0.02 0.03 0.01 0.01 Not Found Not Tested 0.01 0.02 0.05 0.05 0.01 Trace 0.02 0.03
U.S. Dept. of Imt., Geological Survey, Bull. 422 (1910), 192.
2 Wagner and Ross, “A Modified Method for the Determination of Fluorine with Special Application t o the Analysis of Phosphates,” THIS JOURNAL, 9 (1917), 1116; and Adolph, J . A m Chem. Soc., 37 (1915), 2500. 8 Chromium when present in amounts over 0.015 per cent CrzOa presents a rather difficult problem in this method as the solution has t o be kept alkaline to prevent the escape of fluorine, and chromium is not easily reduced in a1 aline solution (to precipitate as chromium hydroxide). It might possibly be removed in a solution slightly acid with acetic acid using silver nitrate as a precipitant. 4 For composition of these soils with respect to other elements see U. S. Dept. Agr., Bull. 122. I n some cases samples of soils of the particular type could not be obtained from the same location. In these cases samples. from as near this location as possible were used.
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Fluorine occurs in the soils examined in amounts averaging 0.03 per cent, approximately t h e same concentration as some of the rarer elements, namely, vanadium, zirconium, and strontium. The soils carrying with them stones made up of mica schist (Hagerstown loam, York silt loam, and Gloucester stony loam) contained the relatively higher amounts of fluorine. SUMMARY
The original source of fluorine in the soil (average
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composition 0 . 0 3 per cent fluorine) in such minerals as biotite, tourmaline, muscovite, apatite, fluorite, and phlogopite. Higher content of fluorine may be expected in soils carrying larger amounts of mica. The roots of t h e plants absorb it and transmit i t t o the animals consuming these plants. Animals also obtain fluorine from spring water. BUREAU O F SOILS DEPARTMENT O F AGRICULTURE WASHINGTON, D . C.
LABORATORY AND PLANT A SCRUBBER FOR AMMONIA DISTILLATIONS By B. S . DAVISSON Received January 21, 1919
“wo of the most glaring errors encountered in ammonia distillations are those from entrained alkali a n d the soft glass used in the construction of distilling bulbs and adapters. I t becomes necessary t o eliminate these errors when determining small amounts of nitrogen where i t is of importance t o determine small differences, as in plant and bacterial nutrition studies. The error from t h e solubility of the soft glass can be eliminated by using apparatus made of Pyrex glass. This glass has been found t o be superior t o any other glass for use with weak acids and, furthermore, i t does not show a tendency t o become brittle on continued use. ’The Hopkins bulb, which has been long in use, does not prevent alkali from passing into t h e receiving acid. I t has been found in this laboratory t h a t t h e entrained alkali can be satisfactorily removed when t h e vapors are scrubbed through water previous t o condensation. Several scrubbers have, therefore, been constructed. The one found most suitable is made of Pyrex glass and is shown in Fig. I . The large b u l b has a capacity of 2 0 0 cc., which gives i t a satisfactory condensing surface. T h e small bulb on t h e inlet tube has three openings in t h e same horizontal plane. The first steam, which passes into the scrubber, condenses on the surface of the bulb and flows down about t h e small bulb and there acts as a scrubbing solution for the remaining vapors. As soon as the water becomes hot it is subjected t o a long period of steam distillation. A period of 3 0 min. in which about 90 cc. of distillate are collected in the first 2 0 min. permits the accumulation of about 1 5 t o 20 cc. of solution in t h e scrubber. This solution is, of course, neutral or slightly alkaline and t h e long period of steam distillation removes all the ammonia from the solution. A great many of these solutions have been tested with Nessler’s a t t h e end of t h e distillation and in no case was ammonia found. As soon as t h e distillation is finished and t h e flame removed, t h e solution is sucked back into the distilling flask. T h e procedure of distillation used in this laboratory consists in steaming for 15 min. after draining t h e condensers, and it is desirable, although not essential, t h a t t h e adapter be provided with a small
perforated bulb. This will insure better scrubbing of the steam than is accomplished with a straight tube. The adapter recommended is shown in Fig. 2 . Some d a t a are presented here t o show the errors of the distilling apparatus commonly employed for ammonia distillation and for t h e accuracy obtainable with t h e new devices attached t o t h e tin condenser. The tin condenser used for obtaining these d a t a had never been employed for ammonia distillations but had been used for preparing distilled water. The solutions were distilled a t such a rate t h a t about go cc. of distillate were collected in 2 0 min. The condenser was then drained and the distillation continued for 15 min. The receivers were removed, cooled, and t h e contents titrated. N / j o sulfuric acid and sodium hydroxide were used as titrimetric standards.
FIO.1
The d a t a recorded in Table I were obtained by distilling ammonia-free water, and the error shown is due t o t h e solubility of the soft glass of the Hopkins
