INDUSTRIAL AND ENGINEERING CHEMISTRY
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An example of the calculation is given below: Paste stirred with water for 60 seconds Additional stirring 10 seconds (trial) New sample stirred with water for 65 seconds (Outflow time with glycerol solution for this pipet is 170 seconds) Initial outflow time Final outflow time
Outflow Time Sec. 181.5 164.5 171.2 171.2
VOL. 7, NO. 3
Various amounts of different enzyme preparations must be used in order to obtain a liquefaction within 50 to 90 per cent decline in viscosity after 1 hour a t 21’ C. This range has been chosen as most suitable for accurate measurements. Table I11 gives the concentration of enzymic materials of various strengths in milligrams per 10 ml. necessary for proper application of the method.
56.5 ___
Ranen -..~ ~ _ . Outflow time with sample (10 mg. per 10 ml.) after 1 hour at 21’ C. Decline in outflow time: 171.2 - 91.8 = 79.4 seconds 7940 Per cent decline: 114.7 6g’2
114.7
TABLE111. ENZYMIC MATERIAL REQUIRED FOR ANALYSIS OF DIFFERENT PREPARATIONS
91.5
Liquefons per Gram 1-3 2-6 5-15 10-30 20-60 50-150 100-300 200-600 500-1500 1000-3000
Mg. of starch liquefied (Table 11): 1409 Loglo L = (S - 1078) X (0.000565) where S = mg. of starch liquefied L = liquefons per 10 ml. 331 X 0.000565 = 0.1570 LogioL L = 1.538
Since 10 mg. of the sample were used and this figure must be related to 1 gram of the sample, the result should be multiplied by 100. The alpha-amylase concentration of the sample is measured by the liquefon content, which is 154 liquefons per gram. Its liquefying power a t zero time is 3850 mg. of dry starch per minute. Table I1 gives a convenient tabulation of data obtained from the liquefon-starch equation for the experimental range of 50 to 90 per cent decline in viscosity.
Preparation of Enzyme Solution Using barley malt (diastatic or pale), 5 grams of malt are weighed into a 1000-ml. flask, 26 grams of sodium chloride are added, and the flask is filled up to the mark, After standing for 1 hour at room temperature with occasional shaking, it is filtered, rejecting the fist 100 ml. of filtrate, 100 ml. of the filtrate are transferred into a 1000-ml. flask (or 60 ml. into a 500-ml. flask), and the flask is filled up to the mark. In case of diastatic malt sirup 2, 6, 10, or 15 grams should be weighed (accordingto strength) and 25 grams of sodium chloride added, in the same manner as in the above sample.
Enzymic Material per 10 MI. Infusion Mg. 1000 600 200 100 60 20 10 5 2 1
Acknowledgment The authors wish to express their thanks to C. N. Frey, H. C. Gore, and Q. Landis for their valuable suggestions and keen interest in this work.
Literature Cited Fletcher, L., and Westwood, J. B., J. Inst. Brewing, 36,550 (1930) Gore, H. C., and Jozsa, S., IND.ENG.CHEM., 24,102 (1932). Ibid., 24, 99 (1932). Johnston, W. R., and Jozsa, S., J. A m . Chem. SOC.,57, 701 (1935). Joasa, S., and Gore, H. C., IND.ENQ.CHEM.,24,95 (1932). (8) Ibid., Anal. Ed., 2,28 (1930). (7) Willaman, J. J., Clark, E. W., and Hager, 0. B., Biochem. Z . , 258,94 (1933).
(1) (2) (3) (4) (5)
RncmIvmD May 28, 1934. Presented before the Division of Biologics Chemistry a t the 86th Meeting of the American Chemical Society, Chicago, Ill., September 10 to 15,1933.
A Simple and Sensitive Test for p-Phenylenediamine OSCAR HEIM, 112-35 Dillon St., Jamaica, L. I., N. Y.
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CCORDING to Erdmann (S), themost sensitive test for p-phenylenediamine is the white precipitate of quinone dichlorodiimide produced with sodium hypochlorite, and he recommends diazotation and coupling with &naphthol disulfonic acid (2) for its detection in fur. There are a number of other tests (1, C), but all have been found unsuitable for detecting the small residual quantities of p-phenylenediamine occasionally present in black dyed fur. The basis of the present test, originally intended to discover small amounts of p-phenylenediamine in fur which could not be found by tests commonly found and recommended for this purpose, is the formation of indamine when a mixture of pphenylenediamine and aniline is oxidized.
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tion (1 drop of aniline in 50 cc. of water), mix, and add a few cry% tals of potassium persulfate. The appearance of a blue-green color within about 5 seconds indicates the presence of p henylenediamine or its derivatives in which the (toxic) p-$amine structure has been preserved-for example, p-toluenediamine sulfate, which can be considered the salt of a methyl-substituted pphenylenediamine, or dimethyl-pphenylenediamine. The test is a sensitive one: 0.05 cc. of a 0.00001 per cent aqueous solution (equivalent to 0.0008 mg. or 0.5 gamma of pphenylenediamine) will give a distinct coloration. Interfering substances do not present difficulties. Other amido compounds-so-called oxidation dyes which are employed in pelt dyeing, such as amido phenols, m-amido anisol, 0- and mphenylenediamine-do not respond to the test, but if a trace of p-phenylenediamine is present with these substances it will be detected.
Literature Cited NHz
Treat the test specimen with a small amount of a 3 per cent solution of acetic acid-for example,6.452 sq. om. (1 square inch) of fur with 1 to 2 cc. of acid-warm to about 45’ C., squeeze the liquid out into a porcelain crucible, add 1 drop of an aniline solu-
(1) Allen, A. H., “Commercial Organic Analysis,” 5th ed., Philadelphia, P. Blakiston’s Son & Co., 1925. (2) Erdmann, 2.angew. Chem., 18, 1377 (1905). ( 3 ) Ibid., 19, 1053 (1908). (4) Rosenthaler, L., “Der Nachweis organischer Verbindungen,” 2nd ed., Stuttgart, Verlag von Ferdinand Enke, 1923. RECEIYED March 26, 1935.
