V O L U M E 1 9 , NO. 3, M A R C H 1 9 4 7
Iron. Dissolve 2 grams in 45 ml. of water, and add 2 ml. of hydrochloric acid, a few crystals of ammonium persulfate (30 to 50 mg.), and 3 ml. of a 30% solution of ammonium thiocyanate. Any red color produced should not be more than is produced by 0.02 mg. of iron in an equal volume of solution containing the quantities of reagents used in the test.
Specifications Previously Published (1) Committee on Analytical Reagents, I n d . Eng. Chern.. 17, 756 (1925). (2) Ibid., 18, 636, 759 (1926). (3) Ibid., 19, 645 (1927). (-1) Ibid., 19, 1369 (19271.
*
215 (5) Ibid., 20, 979 (1928). (6) (7) (8) (9) (10) (11) (12) (13)
ISD. ENG.CHEM.,A N ~ LED., . 1, 171 (1929). Ibid., 2, 351 (1930). Ibid., 3, 221 (1931). Ibid., 4, 154 (1932). Ibid., 4, 347 (1932). Zbid., 5, 289 (1933). Zbid., 12, 631 (1940). Ibid., 16, 281 (1944).
PRESENTED in connection with the report of the Committee on Analytica CHEMICAL SOCIETY, .4tReagents a t the 109th Meeting of the AMERICAX lantic City, S . J.
Preparation of Holocellulose from Nonwoody Plant Material
EMllIETT BENNETT, .Massachusetts .4gricultural Experiment Station, Amherst, OLOCELLULOSE or “skelettsubstanm” represents the entire carbohydrate fraction of extracted plant material in a single unit. The need for such a fraction as a source material for research on cell-wall const’ituents and need for such a product in furthering a similar type of research on economic plants of less \roody nature have long been recognized by wood chemists whd iiave succeeded in making it a reality for wood (2, 3,6 , 6). The object of this investigation was to determine the adaptability of inethods now in use for wood to some other plants. Plant material is usually prepared for the extraction of hemicdluloses (1) by a laborious procedure requiring several days and yielding an unsatisfactory product. The method reported here yields a product known as holocellulose which is almost snow \vhite, substantially free of lignin, contains nearly all the hemicelluloses, and can be obtained in a fen- hours. Such a material \vi11 obviously be of value in cell-wall research. In order to test the efficiency of established procedures, the percentage of furfural retained by the holocellulose and the color of the product were used as indexes, a nearly white color being desirable. Since the nitrogen content of grasses is higher than that of wood, the Lrinount of nitrogen retained in this fraction Tyas determined. EXPERIMENTAL
One should become familiar with the toxic nature of sodium chloride before using it ( 4 ) ,and should perform all work under the flood. The material used and the determinations made are indicated in Table I. Material passing a 25-mesh screen but retained by the 50-mesh screen was used in all cases. Holocellulose was determined substantially as outlined by Wise, Murphy, and D’Addieco (6). To 4 grams of plant material in a 250-ml. beaker, 1.2 grams of sodium chlorite, 8 drops of concentrated acetic acid, and 125 ml. of distilled water were added and stirred until the chlorite dissolved. The beaker was then covered with a watch glass and placed on a steam bath a t 80” C. for 1 hour with occasional stirring. The same amounts of reagents were added t o the beaker every hour for 2 more hours, making a total digestion period of 3 hours. The beaker and contents were cooled to 10” C. in ice water, then filtered through a coarse grade Selas crucible. The material was now nearly completely white and contained only a trace of lignin. The residue was washed six times with ice water and partially dried over calcium chloride in a vacuum desiccator. Final drying was completed in an oven a t 105’ C. The pH of the inibial and final suspension was approximately 4.3 a t 25“ C. Samples of holocellulose which were to be subjected to a furfural determination were filtered through poplin cloth folded as a filter paper. The dry material was removed from the cloth for analySIS.
The original or control material was extracted with i solution
Mass.
of alcohol-benzene for 6 hours, then with ether for 1 hour. Furfural was determined by the phloroglucinol method. Total nitrogen was determined by the conventional Kjeldahl method. The results of the investigation are shown in Table I as the holocelluloee appears to retain a substantial content of ash, which was not removed by the treatment, weights of holocellulose were corrected accordingly. The holocellulose fraction in these cases was not all carbohydrate but contained a relatively high percentage of the original nitrogen of the plant material. Table I. Percentage Content of Holocellulose in Plant 3Iaterials and Furfural and Total Nitrogen Retained by Holocellulose Ash a n d moisture-free basis Analyses
Kentucky Blue Grass
Corncobs
Oat Straw
Timothy Hay
Cornstalks
%
%
%
%
%
Holocellulosea 73.7 78.9 80.6 75.1 78.6 Furfural Original b 13.36 13.50 13.11 12.23 13.21 HolocelluloseC 12.89 12.82 12.78 11.83 13.09 96.5 Yo recovery 95.0 97.5 96.7 99.1 Total nitrogen 2.44 0.34 Original 1.55 1.34 1 14 1.36 0.11 Holocellulose 0.68 0.71 0.37 55.7 32.4 Yo retained 43.9 53.0 32.5 a Average deviation for these determinations was i o . ? % . h e Average of fire or six determinations; other determinations were made in duplicate or triplicate. ~
___-_____ CONCLUSIONS
The sodium cliloi,ite method used for the preparation of liolocellulose from wood may be adapted for the same use with nonwoody tissue. The older preliminary procedure for this kind of plant tissue involves 2 to 3 days’ time, while the one described here seems to yield a product of satisfactory color and furfural content in 2 to 3 hours. However, when the product is obtained in the manner described, from 30 to 50% of the original nitrogen of the plant material may also be included. LITERATURE CITED
(1) Buston, H. W., Biochem. J.,28, 1028 (1934). (2) Freeman, R. D., “Wood Chemistry”, Chapter 17, edited by L. E. Wise, New York, Reinhold Publishing Corp., 1944. (3) Ritter, G. J., and Kurth, E. F., IND.ENG.CHEW,25, 1250 (1933). (4) Taylor, M. C., White, J. F., Vincent, G. P., and Cunningham, G. L., Ibid., 32, 899 (1940). ( 5 ) Wise, L. E., IND.ENG.CHEM., ANAL.ED.,17, 63 (1945). (6) Wise, L. E., Murphy, Maxine, and D’Addieco, A. A., Puper Trade J . , 122, No. 2, 35 (1946). CONTRIBUTIOS 608, Massachusetts Agricultural Experiment Station.
