January 15, 1933
INDUSTRIAL AND ENGINEERING CHEMISTRY
method IV. This shows that all the fourteen samples contained reversion products as well as amino compounds. The quantity of the reversion products, expressed as sucrose, in the refinery blackstraps varies from 0.64 to 1.32 per cent, averaging 1.12 per cent; and the quantity of amino compounds from 0.40 to 0.89 per cent, averaging 0.61 per cent. I n the filtered sirups there are found 0.10 to 1.03 per cent, averaging 0.57 per cent, of reversion products, and 0.11 to 0.66 per cent, averaging 0.29 per cent, of amino compounds, all again expressed as equivalent sucrose. Expressed as asparagine or aspartic acid, the content of amino compounds in blackstraps and refinery sirups is, according to data given by Ambler (1) and by Browne (4), very much higher, in the neighborhood of 2 to 2.5 per cent. Leaving out Jackson and Gillis method 11, and comparing the results of the other three methods for all the three groups of products analyzed, it is found that the plain acid method gives the highest average results, 0.10, 0.26, and 0.15 per cent, respectively, higher than Jackson and Gillis method IV. The average figures by this last-named method again exceed those of the invertase method by 0.28, 0.51, and 0.47 per cent, respectively, owing to the differential effect of reversion products and of amino compounds. Upon making individual comparisons, it is found that Jackson and Gillis method IV gives a higher result than the invertase method in twenty-one cases. I n all of these the reversion products, expressed as sucrose, exceed the amino compounds, expressed the same way; in the remaining two cases, samples 7 and 19, the opposite is true, as actually shown in sample 7 by comparison with the result of Jackson and Gillis method 11. The plain acid method gives the highest result in nine-
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teen cases, including all the raw sugar blackstraps, intermediate results in three, and the lowest result in one case, again proving the statement made above with regard to this method. The invertase method gives the lowest result in all samples but three, I n two of these exceptions, samples 7 and 19, this is due to the preponderance of amino compounds over the reversion products, as already explained. I n the last remaining case, sample 13, the acid method happens to give the lower result, but with a difference of only 0.03 per cent, which is well within the limit of error. The application of the results, previously obtained with artificial mixtures, to the analysis of actual cane products has thus shown that Jackson and Gillis methods I1 and IV, used in conjunction with the invertase method, give valuable indications with regard to the relative quantities of reversion products and of amino acids present in such products.
LITERATURE CITED (1) Ambler, 3. A.,Intern. Sugar J . , 29,439 (1927). (2) Assoc. Official Agr. Chem., Official and Tentative Methods, 3rd ed., p. 370 (1931). (3) Ibid., p. 372. (4) Browne, C. A., and Blouin, R. E., La. Sugar Expt. Station, Bull. 91, 93 (1907). ( 5 ) Jackson and Gillis, Bur. Standards, Sci. Paper 375,184 (1920). (6) Jackson and Gillis, Ibid., p. 187. (7) Zerban, J . Assoc. O$cciaZAgr. Chem., 8,384(1925);9,166(1926); 10,183(1927); 11,167(1928);12,158(1929);13,188(1930); 14,172 (1931). (8) Zerban, Orig. C m . 8th Intern. Congr. Appl. Chem., 8, 103 (1912). RECEIVEDJuly 19, 1932. Presented before the Division of Sugar Chemistry at the 84th Meeting of the American Chemical Society, Denver, Colo., August 22 t o 2 6 , 1932.
A Rapid Method for Distinguishing Bleached Sulfate from Bleached Sulfite RALPHW. SHAFFER,MacAndrews & Forbes Co., Camden, N. J.
N
0 STAIN appears to be known which clearly differentiates between bleached sulfate and bleached sulfite in pulp and paper. The following formula affords a simple method of indentification. One gram of sodium carbonate is dissolved in 175 cc. of distilled water, and to this solution 1 gram of c. P. brazilin is added, stirring until dissolved. The solution gives sharper differences if used fresh. If retained for future use, air should be excluded. The solution may be applied directly to the sample to be identified, or if the preparation of a microscope slide is desired, the procedure is as follows: One gram of pulp or paper is disintegrated by boiling for 10 minutes with distilled water. The fiber is screened and shaken up with 50 cc. of water. The micro-slide is prepared by placing 4 drops of the fiber suspension on the slide and allowing to dry. The slide is then plunged for an instant into the stain solution prepared as directed above. Excess stain solution is removed with hardened filter paper, a few drops of U.8. P. white paraffin oil are placed on the slide, and any excess oil is removed. Bleached sulfite is stained a wine-red color, and bleached sulfate (Kraft) is stained a purple color by the brazilin solution. If the analyst encounters a slide containing some fibers which appear doubtful as to identification, he should prepare
a duplicate slide and test it with Lofton-Merritt stain, in order to eliminate the possibility of reporting as bleached fibers some which in reality are partially bleached. If the Lofton-Merritt stain shows a sulfate reaction, and yet with brazilin the fibers react to produce a lighter shade than the deep purple of the fully bleached sulfate, the obvious conclusion would be that these fibers are partially bleached sulfate. Similarly, if the Lofton-Merritt stain shows a sulfite reaction, and yet the fibers react with brazilin to produce a lighter shade than the vivid wine-red of the fully bleached sulfite, the conclusion would be that these fibers are partially bleached sulfite. To emphasize the supersensitivity of this stain to all contamination, the following explanatory data are added: METHODOF DISINTEQRATION. The standards of the Technical Association of the Pulp and Paper Industry have been adopted in all other microanalyses, and a t the beginning of work on brazilin every effort was made to have the technic conform to those standards. This was found impossible, however, because the stain is so very sensitive. The slightest trace of acid, or addition or subtraction of alkali, makes the stain worthless, and, although the author has tried the T. A. P. P. I. method of disintegration many times for this stain, results have never been successful. An explanation is that all the sodium hydroxide is not washed out after boiling
ANALYTICAL EDITION
36
and hence interferes with the reaction. In the case of hard sized papers, the boiling time is increased in order to get the proper disintegration. DRYIKGOF SLIDE. The slide may be either dried or blotted. However, the author’s reason for preferring drying is solely to eliminate one more possibility of contaminationthe blotting medium. METHODOF STAINING. There may also be some question as to whether it is better to immerse the slide in the staining solution or to drop the solution upon the slide. Either method of staining is satisfactory. However, if the dropping method is used, sufficient stain should be dropped on the slide from a pipet to cover all fibers a t once, since the most
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important part of the staining procedure is to remove the excess stain instantly. No mixing of the stain with the fibers is necessary. In fact it is detrimental, as this stain permeates the fibers instantly on contact. There may also be some question as to the economy of immersing the slide, instead of dropping the stain upon the slide. For analyses which make only one or two slides necessary, only a portion of the specified amount is made up. C. P. brazilin, made by the MacAndrews & Forbes Co., 200 Fifth Ave., New York, N. Y., at 50 cents per gram, is used. The oil immersion is not absolutely essential, but sharper differentiation can be obtained with oil than with water, R E C E I V July ~ D 7, 1932.
Equipment for Laboratory Fumigations with Hydrocyanic Acid With Controlled Temperature and Humidity H. L. CUPPLES,Bureau of Chemistry and Soils, Department of Agriculture, Whittier, Calif.
H
YDROCYANIC acid is used extensively for field fumigations of citrus trees, particularly in the control of the red scale, Chrysomphalus aurantii. I n field work it is very difficult to duplicate exactly any given treatment, owing primarily to the lack of control over meteorological conditions. I n order to pursue various research problems relating to the toxicity of hydrocyanic acid to red scale, it is of great advantage to be able to make fumigations in the laboratory under closely controlled conditions. This paper describes an assembly which has been found satisfactory for such experiments. Provision is made for the control of hydrocyanic acid concentration, relative humidity, time, and temperature of treatment.
FUMIQATION CHAMBER Laboratory toxicity tests may be made by fumigating lemons which are moderately heavily infested with red scale. The lemons are cut with stems about 4 inches (10 cm.) long.
MINUTES
FIGURE 1
They may be kept in good condition for a sufficient length of time after a fumigation to provide for satisfactory mortality counts. The fumigation chamber, which will conveniently accommodate four lemons, is adapted from a glass desiccator, 200 mm. inside diameter, with ground-on cover tubulated to accommodate a rubber stopper. Inlet and out-
let tubes for the air-hydrocyanic acid mixture enter through the rubber stopper, the inlet tube opening a t a point near the bottom of the desiccator and the outlet tube opening near the extreme top. Tests with fumes of ammonium chloride, using a gas flow of 6 liters per minute, have shown that sufficient turbulence is produced within the desiccator to insure a uniform distribution of the hydrocyanic acid. A support is provided within the desiccator to which the lemons are tied, and when the lemons are in place the desiccator may be covered and entirely immersed in a water thermostat. The bottom portion of the desiccator contains enough metallic lead to sink the desiccator to the bottom of the thermostat. The inlet and outlet tubes for the gas mixture are long enough to protrude above the surface of the water, and they are connected to the other units with short rubber connectors. I n the fumigation of red scale with hydrocyanic acid it is desirable, for maximum effectiveness, that the concentration be increased to its maximum value within a short period of time (2,s). Although this requirement would not seem to be 60 vital for the performance of comparative laboratory tests, nevertheless it has seemed desirable to obtain a comparatively rapid increase of concentration. This has been attained by using a fumigation chamber having the relatively small volume of 4 liters, and by supplying the air-hydrocyanic acid mixture a t the rate of 6 liters per minute. Experiments have been made to determine the rate of increase of concentration a t the start of a fumigation, and the rate of decrease of concentration a t the close, a t which time the fumigation chamber is usually swept out with air. The gas samples for these analyses were taken from the outlet tube leading from the top of the chamber, and thus represent a somewhat less favorable situation than a t a point centrally located within the fumigation chamber. These results are represented graphically in Figure 1.
FLOW DIAGRAMAND DESCRIPTION OF APPARATUS A flow diagram of the assembly is shown in Figure 2. Air enters through the flowmeters, A and B, and is finally exhausted to the atmosphere outside the building by a motordriven exhaust pump. The major portion of the air, about 6 liters per minute, enters through flowmeter A and is brought
