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INDUSTRIAL A N D ENGiINEERING CHEMISTRY
that the quickest and most accurate way to make this determination in a water solution of the sample is to use 1 gram of the sample, drop into a beaker containing at least 200 cc. of distilled water, and stir frequently over a period of onehalf to three-quarters of an hour, then filter, This gives on these products a clear filtrate. This is diluted up to a volume of about 450 to 500 cc. Four or five drops of a 0.1 per cent solution of methyl orange indicator are then added and the solution is titrated with standard alkali. The neutral point is determined by comparison with a beaker containing the same volume of distilled water and methyl orange. Considerable work has been done to find a way to procure a standard of the general type of material analyzed, against which an alkali solution can be standardized. The value of such a standard can be readily appreciated. Of the several methods tried the one proposed by Wiley in his “Principles of Agriculture,” offers the most promise. When using this method as outlined, it has been found necessary to carry a sample of the calcium carbonate used through the same procedure, and in addition on these products the proper dilution factor must be used to prevent decomposition of monocalcium phosphate with consequent production of free HgPOa. Extraction of free HsP04 from the sample by means of absolute alcohol and subsequent determination of PzO, volumetrically gives considerably higher results on samples containing moisture than on dried portions of the same sample. This is probably due to a change in the composition of sample during drying operation.
Vol. 17, No. 3
A Double-Reacting Turmeric Paper’s2 By William Brinsmaid ILLINOIS DEPARTMENT OF AGRICULTURE, CHICAGO, ILL.
ERCOLATE 30 grams of freshly ground turmeric with a mixture of 180 cc. of 95 per cent alcohol and 120 cc. of water. Place the resulting liquid in a beaker and take to dryness on a steam bath. The residue will consist of a deep, red oily mass and a dry, brown scaly material. Add 10 cc. of clear alcohol and the red, oily mass will go into solution. If the first treatment with alcohol does not dissolve all the red, oily material, add small portions of alcohol with decantation until dissolved. The brown, scaly material will not dissolve in the alcohol. Filter through a paper, washing out the paper with clear alcohol. Add alcohol to make the liquid up to 100 cc. Prepare a paper pulp by disintegrating filter papers that have been washed with hydrochloric and hydrofluoric acids. Preparation of Test Paper a n d M e t h o d of Use
For each gram of dry paper pulp, place in a beaker 75 cc. of water and 15 drops of the turmeric solution. Add the paper pulp and stir thoroughly, breaking up any lumps. Place on a steam bath and allow to stand, .with occasional stirring, until the paper has absorbed all the color. Filter on a Buchner funnel with a fitted filter paper and suction, so that when the pulp has been sucked as dry as possible D e t e r m i n a t i o n of Moisture there will remain a layer of pulp about 3 mm. thick. Do . It is the opinion of the writers that improper exposure of not wash the pulp. Remove this on the bottom paper and the sample to the atmosphere before and during analysis is dry a t a gentle heat. The paper pulp will be colored a the chief source of error in this determination. These prod- clear lemon yellow. When dry, peel away the bottom ucts are very hygroscopic in nature. Great care must be paper and with shears cut the turmeric paper into small taken in handling the sample, and desiccators in which it is squares of about 7 or 8 sq. mm. Place in a tight container placed for the purpose of cooling must contain fresh, efficient, and keep in a dark place. dehydrating agents. Concordant results can be procured by For each test desired place one of the paper squares in a placing the sample (quite universally 2 grams in weight) in a depression in a spot plate. Moisten with a few drops of the round aluminium dish about 51 mm. (2 inches) in diameter solution to be tested. The paper should be thoroughly and 13 mm. (0.5 inch) deep, having a tight-fitting cover, placing moistened and a slight excess of solution does no harm. in a water oven at temperature of boiling water at the par- Place the spot plate and paper in a warm place and allow ticular altitude where determination is being made, and leav- to dry. The full heat of a steam bath is too high and may ing for 5 hours. The oven is not opened at any time while discolor the paper. It is essential that the paper be thorthe sample is drying, After 5 hours the sample is quickly oughly dry, but it must not be overheated. When dry the covered and put into an efficient desiccator to cool. paper will be a pink or cherry color if boric acid or its salts One very interesting point disclosed in connection with this were present. To confirm the test, place a drop or two of determination is the error encountered due to regrinding of 0.1 N sodium hydroxide solution on the pink paper. If the sample to a finer mesh than that universally specified for color is due to boric acid or its salts the paper will immediately phosphatic materials. As has been pointed out in a former turn a clear blue. paper by Mr. Larison, this leads to serious changes in the Notes constitution of the material. First, undue exposure to atFreshly ground turmeric is specified because ground turmeric mosphere, coupled with heat generated in grinding operation, that is old and has been exposed to light will bleach and lose changes moisture content. Second, these products invaria- some of its coloring power. bly contain free phosphoric acid, which when rubbed between Taking the percolation to dryness on the steam bath throws grinding surfaces adheres to these surfaces and becomes very out from the solution certah coloring matter in the turmeric hard to remove and reduce to a powder. Furthermore, which is insoluble in alcohol but is soluble in water. This is not responsive to the boric acid test, and it disguises adhering particles, owing to their great affinity for water, take coloring or inhibits the blue confirmatory reaction. Its removal is up a considerable percentage of water in a comparatively therefore necessary. short time. Several grades of filter paper were made into pulp and tested, New Proofing Process-A new and cheap process of proofing which it is claimed will make any textile fabric-whether wool, cotton, or silk-absolutely waterproof, is said to have been discovered by Leigh Murray, of England, who has been engaged on this problem for five years. The proofing is noninflammable, odorless, hygienic, and is claimed to be adaptable to the waterproofing of any material. It is further reported that a company is being formed under the title of the British Murcolene Proofing Company to develop the process.
but none were as satisfactory as pulp made from filter paper washed with hydrochloric and hydrofluoric acids. One cheap grade of filter paper gave a direct test for boric acid. Strips of filter paper dipped in the turmeric solution and dried will give the reactions, but the colors are not so clear and decided as on the squares, especially when the amount of boric acid present is small. Received December 18, 1924. For another method of making the turmeric solution and for mention of some substances interfering with the test see Chamot and Cole, THIS JOURNAL, 10, 48 (19181. 1 2
